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Plant lipid transfer proteins (LTPs) play essential roles in various biological processes, including anther and pollen development, vegetative organ development, seed development and germination, and stress response, but the research progress varies greatly among Arabidopsis, rice and maize. Here, we presented a preliminary introduction and characterization of the whole 65 LTP genes in maize, and performed a phylogenetic tree and gene ontology analysis of the LTP family members in maize. We compared the research progresses of the reported LTP genes involved in male fertility and other biological processes in Arabidopsis and rice, and thus provided some implications for their maize orthologs, which will provide useful clues for the investigation of LTP transporters in maize. We predicted the functions of LTP genes based on bioinformatic analyses of their spatiotemporal expression patterns by using RNA-seq and qRT-PCR assays. Finally, we discussed the advances and challenges in substrate identification of plant LTPs, and presented the future research directions of LTPs in plants. This study provides a basic framework for functional research and the potential application of LTPs in multiple plants, especially for male sterility research and application in maize.

This work describes a base-mediated borylsilylation of benzylic ammonium salts to synthesize geminal silylboronates bearing benzylic proton under mild reaction conditions. Deaminative silylation of aryl ammonium salts was also achieved in the presence of LiOtBu. This strategy which is featured with high efficiency, mild reaction conditions, and good functional group tolerance provides efficient routes for late-stage functionalization of amines.

Grain yield is the most critical and complex quantitative trait in maize. Kernel length (KL), kernel width (KW), kernel thickness (KT) and hundred-kernel weight (HKW) associated with kernel size are essential components of yield-related traits in maize. With the extensive use of quantitative trait locus (QTL) mapping and genome-wide association study (GWAS) analyses, thousands of QTLs and quantitative trait nucleotides (QTNs) have been discovered for controlling these traits. However, only some of them have been cloned and successfully utilized in breeding programs. In this study, we exhaustively collected reported genes, QTLs and QTNs associated with the four traits, performed cluster identification of QTLs and QTNs, then combined QTL and QTN clusters to detect consensus hotspot regions. In total, 31 hotspots were identified for kernel size-related traits. Their candidate genes were predicted to be related to well-known pathways regulating the kernel developmental process. The identified hotspots can be further explored for fine mapping and candidate gene validation. Finally, we provided a strategy for high yield and quality maize. This study will not only facilitate causal genes cloning, but also guide the breeding practice for maize.

Phytochemical investigation on the 95% EtOH extract of the Traditional Chinese Medicine (TCM) Euphorbia royleana (Ba-wang-bian in Chinese) led to the isolation of 11 diterpenoids (1–11) and two triterpenoids (12 and 13). Among them, compounds 1 and 2 were new ingenane and ingol diterpenoids, respectively. Their structures were elucidated by a combination of spectroscopic analyses (1 D and 2 D NMR, HRMS, ECD, UV, and IR data) and chemical methods. Compounds 12 and 13 exhibited moderate cytotoxicities in vitro against human lung cancer cell line A549 with IC50 values of 14.84 ± 0.56 and 27.11 ± 1.65 µM, respectively.

One therapeutic approach for Alzheimer's disease is to inhibit the cleavage of the amyloid precursor protein (APP) by γ-secretase. At the beginning of a series of studies from our laboratories, a series of novel γ-amino alcohols (1) were found to possess γ-secretase inhibitory activity and Notch-sparing effects. A new one-pot synthesis of γ-amino alcohols and the structure-activity relationship (SAR) of these analogs will be discussed.

Wnt/β-catenin signaling is upregulated in triple-negative breast cancer (TNBC) compared to other breast cancer subtypes and normal tissues. Current Wnt/β-catenin inhibitors, such as niclosamide, target the pathway nonspecifically and exhibit poor pharmacokinetics/pharmacodynamics in vivo. Niclosamide targets other pathways, including mTOR, STAT3 and Notch. Novel benzimidazoles have been developed to inhibit Wnt/β-catenin signaling with greater specificity. The compounds SRI33576 and SRI35889 were discovered to produce more cytotoxicity in TNBC cell lines than in noncancerous cells. The agents also downregulated Wnt/β-catenin signaling mediators LRP6, cyclin D1, survivin and nuclear active β-catenin. In addition, SRI33576 did not affect mTOR, STAT3 and Notch signaling in TNBC and noncancerous cells. SRI35889 inhibited mTOR signaling less in noncancerous than in cancerous cells, while not affecting STAT3 and Notch pathways. Compounds SRI32529, SRI35357 and SRI35361 were not selectively cytotoxic against TNBC cell lines compared to MCF10A cells. While SRI32529 inhibited Wnt/β-catenin signaling, the compound also mitigated mTOR, STAT3 and Notch signaling. SRI33576 and SRI35889 were identified as cytotoxic and selective inhibitors of Wnt/β-catenin signaling with therapeutic potential to treat TNBC in vivo.

Tremendous efforts have been devoted to increasing the CO2 capture performance of porous materials, especially for low CO2 concentration environments. Here, we report that hydrazine can be used as a diamine short enough to functionalize the small-pore metal–organic framework [Mg2(dobdc)] (H4dobdc = 2,5-dihydroxyl-1,4-benzenedicarboxylic acid). By virtue of the ultrahigh concentration of free amine groups (6.01 mmol g−1 or 7.08 mmol cm−3) capable of reversible carbamic acid formation, the new material [Mg2(dobdc)(N2H4)1.8] achieves a series of new records for CO2 capture, such as single-component isotherm uptakes of 3.89 mmol g−1 or 4.58 mmol cm−3 at the atmospheric CO2 concentration of 0.4 mbar at 298 K and 1.04 mmol g−1 or 1.22 mmol cm−3 at 328 K, as well as more than a 4.2 mmol g−1 or 4.9 mmol cm−3 adsorption/desorption working capacity under dynamic mixed-gas conditions with CO2 concentrations similar to those in flue gases and ambient air.

We investigated the effects of a dual-frequency frequency-sweeping ultrasound (DFFSU) treatment on the functional properties and structure of zein. The solubility of ultrasound-treated zein proteins increased slightly but significantly as the treatment time increased. The results showed that the DFFSU treatment had an obvious influence on the mean particle size and the size distribution. A significant (P < 0.05) increase in the size of the particles with respect to time was observed after a sonication time of more than 20 min in zein solutions. Differential scanning calorimetry results showed that sonication alters the thermal behavior of zein. Circular dichroism spectra showed a small increase in the percentage of ordered structure elements within the protein molecule. After 60 min of ultrasonication, the percentage of α-helix structures increased by 0.9%, whereas the percentage of β-sheets and β-turns decreased by 0.5%. Microstructural analyses by scanning electron microscopy showed that several microho...

γ-Secretase is one of two proteases directly involved in the production of the amyloid β-peptide, (Aβ) which is pathogenic in Alzheimer’s disease. Inhibition of γ-secretase to suppress the production of Aβ should not block processing of one of its alternative substrates, Notch1 receptors, as interference with Notch1 signaling leads to severe toxic effects. In the course of our studies to identify γ-secretase inhibitors with selectivity for APP over Notch, 1 [3-(benzyl(isopropyl)amino)-1-(naphthalen-2-yl)propan-1-one] was found to inhibit γ-secretase-mediated Aβ production without interfering with γ-secretase-mediated Notch processing in purified enzyme assays. As 1 is chemically unstable, efforts to increase the stability of this compound led to the identification of 2 [naphthalene-2-carboxylic acid benzyl-isopropyl-amide] which showed similar biological activity to compound 1. Synthesis and evaluation of a series of amide analogs resulted in benzofuranoyl amide analogs that showed promising Notch-sparing γ-secretase inhibitory effects. This class of compounds may serve as a novel lead series for further study in the development of γ-secretase inhibitors.

In search for novel lead compounds as γ-secretase inhibitors, analogs of aminopyrido[2,3-d]pyrimidin-7-ones (I) were synthesized and evaluated for inhibitory effects on amyloid –β-peptide production and cleavage of the Notch1 receptor mediated by γ-secretase. Selected pyridopyrimidines, such as 1, 8, 9, 10, 11 and 16 are γ-secretase inhibitors that did not have an effect on Notch1 receptor processing.

Recently, we designed and synthesized a series of chiral ferrocenes and cyclophanes with and without planar chirality. In this review, our own work on the, applications of these ligands in transition-metal catalyzed enantioselective carbon–carbon bond forming reactions, including asymmetric allylic substitution reactions of ketone imino esters, enolates of simple ketone and mono substituted allyl substrates, intermolecular Heck reaction of dihydrofuran and pyrrol, addition reactions of diethylzinc to carbonyl derivatives are presented with emphasis on the regio- and enantioselectivities of the reactions. The role of planar chirality of ferrocenes and cyclophanes as well as some of their structural features influence the reactivity and enantioselectivity in asymmetric catalysis are also discussed.

Synthetic approaches to the total synthesis of plakortone B, as well as diastereoselective nucleophilic additions to furyl aldehyde and furyl sulfonylimine employing chiral 3-boronates as auxiliary are presented.

The first example of a direct aldehyde–ketone coupling using the secondary amine piperidine as base in the presence of MgI2 to generate high selectivity of anti-aldol products from unmodified ethyl ketones in high yield is reported. The coupling reactions were carried out in a one-pot reaction by mixing four reaction components at room temperature. In the case of unsymmetrical ketones, addition was made to the less hindered α-side.

The first time steroselective synthesis of ( Z )-β-bromo Baylis–Hillman ketones has been achieved using a one-pot three-component reaction. The new system uses MgBr 2 as both the Lewis acidic promoter and the bromine source for the Michael-type addition with α,β-acetylenic ketones to form an active β-bromo allenolate intermediate, which in turn attacks various aldehydes to afford β-bromo Baylis–Hillman adducts in good yields and Z -selectivity.

Low-temperature crystal structures of three pyrrolediones (3-5) and a furandione (9) were obtained and compared to structurally related compounds that cannot undergo decarbonylation. Systematic trends in bond lengths and angles are consistent with distortions along the reaction coordinate, in accord with the structure correlation principle of Dunitz. Since the pyrroledione and furandione rings in 3-5 and 9 are planar, these ground-state geometries prefigure the calculated planar, pseudopericyclic transition states.

The efficient and highly stereoselective syntheses of a variety of (Z)-configured, substituted α-(hydroxymethyl)-β-iodo-acrylates from prop-2-ynoate and various aldehydes was achieved. The synthetic protocol involves a simple one-pot coupling reaction under mild conditions, promoted by MgI2, which serves both as a Lewis acid and iodine source for a BaylisHillman-type reaction. All adducts were generated in good-to-excellent yields, the (Z)-isomers being formed in high selectivity (>98%). The conversion of methyl prop-2-ynoate into an active ‘β-iodo allenolate’ intermediate, which then nucleophilically attacks an aldehyde, is proposed as a plausible reaction mechanism.

An asymmetric synthesis of β-iodo-α-(hydroxyalkyl)acrylates has been developed involving conjugate addition of I− to menthyl propiolates to give β-iodo allenolate intermediates which undergo 1,2-addition to form β-iodo Baylis–Hillman products. Modest diastereoselectivities (37–58% de) and excellent yields (80–87%) were obtained when (1R,2S,5R)-(−)-menthol was used as a chiral auxiliary. The two diastereoisomers of the product were separated by silica gel chromatography to give diastereomerically pure products.

An efficient one-pot, three-component coupling reaction for the synthesis of β-iodo-α-(hydroxyalkyl) acrylates has been developed. As the iodine source as well as the Lewis acid mediator, diethyl aluminium iodide undergoes a Michael-type addition with methyl propynoate to form an active β-iodo allenolate intermediate, which in turn attacks various aldehydes or ketones to afford β-iodo Baylis–Hillman adducts in excellent yields with high Z-selectivity.

The FeCl(3)-PPh(3) complex was found to effectively catalyze the electrophilic diamination reaction of electron-deficient alkenes. Improvements on yields and stereoselectivity have been achieved for both alpha,beta-unsaturated carboxylic esters and ketones. Under the new catalytic system, alpha,beta-unsaturated carboxylic esters were found to be superior to their ketone counterparts, which is opposite to the previous (C(3)F(7)CO(2))(2)Rh](2)-catalyzed diamination. The reaction employs readily available N,N-dichloro-p-toluenesulfonamide (TsNCl(2)) and acetonitrile as the nitrogen sources and is very easy to perform at room temperature without the special protection of inert gases. The resulting diamino products belong to imidazolidine analogue and can further strengthen the importance of the new reaction. Modest to good yields (52-84%) and high regio- and stereoselectivity have been achieved for 10 examples.

Highly stereoselective synthesis of (E)-β-bromo Baylis-Hillman ketones has been achieved using a three-component X–C/C–C formation reaction. The synthesis involves the Michael-type addition of TiBr4 to α,β-acetylenic ketones without using any bases and carbonyl coupling with aldehydes. Modest yields (50–65%) and complete E/Z geometric selectivity have been realized for 10 examples.

a,b-Ethyl thioacrylate was difuctionalized by a tandem X-C/C=C bond formation reaction. The new system uses Ti (IV) halide as both the Lewis acidic promoter and the halogen source for the Michael-type addition onto the thioacrylate. The titanium enolate species resulting from Michael-type addition react with aldehydes followed by dehydration to afford trisubstituted olefin products. Complete geometric selectivity (>95%) and up to 72% yield have been obtained for 7 examples.

A substoichiometric amount of titanium tetrachloride was found to be effective to promote and participate in the tandem α-hydroxyalkylation/β-chlorination of α,β-acetylenic ketones in the presence of (n-Bu)4NI. This method provides the concise synthesis of (E)-β-halo Baylis–Hillman adducts. No β-iodo products were detected when using this combination of halogen sources. The reaction process involves 1,4-addition of chloro anion released from TiCl4 onto α,β-acetylenic ketones to give TiCl3–allenolate intermediates followed by the titanium Lewis acid-promoted carbonyl addition. Modest to good yields (53–77%) and excellent E/Z stereoselectivity (>95%) have been obtained for 10 examples.

A three-component electrophilic reaction transforms olefins into imidazoline and diamine derivatives. Rhodium(II) heptafluorobutyrate dimer (2 mol %) was utilized as the catalyst and N,N-dichloro-p-toluenesulfonamide (TsNCl2 ) and acetonitrile as the nitrogen sources. Modest to good yields (45-82 %) and high regio- and stereoselectivity were achieved.

N-Chloro-N-sodium-sulfonamide was found to react with olefins in the presence of copper catalyst to give vicinal haloamine derivatives instead of aziridines. The resulting regio and stereochemistry indicates that this unexpected reaction could proceed through the formation of unprecedented N-chloro-N-copper-2-nitrobenzenesulfonyl aziridinium intermediates, which can increase the successful chance to render the asymmetric version of the aminohalogenation reaction. In addition, this finding provides a more convenient protocol by the use of solely pure NsNClNa for the aminohalogenation reaction as compared to the mixed nitrogen and chlorine sources consisting of NsNCl2 and NsNHNa as previously reported by us. Two new simple olefin substrates, trans-stilbene and styrene, were also found to be effective for this new reaction system.

Transition metal–ligand complex-catalyzed regio- and stereoselective aminohalogenation of cinnamic esters has been developed using p-TsNCl2 as the nitrogen and chlorine sources. Dichloro-(1,10-phenanthroline)-palladium (II) as the catalyst can be handled very conveniently due to its property of less hygroscopic as compared with other aminohalogenation catalysts. The reaction is suggested to proceed through the mechanism involving N-tosyl N-chloro aziridinium intermediate. Eight examples are presented with modest to good yields (56–82%) and excellent stereoselectivity (>10:1).

A series of novel planar chiral N,O-[2,2]paracyclophane ligands were synthesised and applied as catalysts in the enantioselective addition of diethylzinc to aldehydes. The results indicate that the planar chirality of [2,2]paracyclophane, not the central chirality of the oxazoline, is the dominant stereocontrolling element.

The asymmetric catalytic aldol reaction of silyl allenolates with aldehydes has been achieved by using N-C(3)F(7)CO oxazaborolidine as the catalyst. The fluoroacyl group of the catalyst was found to be crucial for control of enantioselectivity. The reaction provides the first enantioselective approach to beta-halo Baylis-Hillman-type adducts.

Tandem diamination of cinnamic esters provides a new approach to anti alkyl Nα-(2-Ns), Nβ-Ac diaminophenylpropionates. The new reaction proceeds to completion within 3 hours at room temperature using N,N-dichloro-2-nitrobenzenesulfonamide (2-NsNCl2) as the nitrogen source in acetonitrile, which is also involved in the reaction process. Seven diamine derivatives have been obtained with good yields and stereoselectivity.

New regio- and stereoselective aminohalogenation of cinnamic esters has been developed using the combination of 2-NsNCl(2)/2-NsNHNa as the nitrogen and chlorine sources and copper(I) triflate as the catalyst. The new procedure provides an efficient synthesis of anti-alkyl 3-chloro-2-(o-nitrobenzenesulfonamido)-3-phenylpropionate derivatives. Nine examples are presented with good yields (62-82%) and stereoselectivity ((5:1)-(30:1)).

A highly stereoselective method for the synthesis of (E)-β-halogeno Baylis–Hillman adducts has been developed. The new method involves a tandem α-hydroxyalkylation/β-chlorination of α,β-acetylenic ketones by using TiCl4 as the chlorine source for α,β-conjugate addition, and concurrently as the Lewis acid promoter for the carbonyl addition. The new system tolerates a broad scope of reactants in which aliphatic and aromatic α-acetylenic ketones can be subjected to the conjugate addition. Both aliphatic and aromatic aldehydes can also be employed as electrophilic acceptors. Good yields (61–88%) and high E/Z stereoselectivity have been obtained for the nine examples which were examined, only in one case was E/Z selectivity of 17/1 observed and the two individual isomers are separable via flash column chromatography.

TiCl4-Mediated Baylis–Hillman and aldol reactions were developed without the direct use of a Lewis base. These processes involve the conjugate addition of TiCl4 to α,β-unsaturated substrates followed by carbonyl coupling. Baylis–Hillman olefins were obtained when α,β-unsaturated ketones were employed as the substrates, whereas β-halogenated aldol products were generated with an α,β-unsaturated N-acyl benzoxalinone as the Michael-type acceptor.

An efficient deprotection of N - p -toluenesulfinyl group of β-branched Baylis–Hillman adducts has been developed by using Amberlite IR-120 (plus) ion-exchange resin in methanol solution at room temperature. Good to quantitative yields have been obtained for six examples. No racemization was detected under the mild conditions. This new method provides a simultaneous deprotection/purification, which has the great advantage over the solution phase deprotection technique of simplicity of work-up.

A new mild procedure has been developed for the synthesis of cis β-bromostyrene analogs with complete Z/E selectivity and good to excellent yields (58.4 - 90.9%). The process involves carboxyl-halo-elimination of cinnamic acid dibromides by using triethylamine in N,N-dimethylformamide at room temperature. A one-pot procedure has also been described for the direct transformation of cinnamic acids to β-bromostyrenes.

A new method has been developed for the synthesis of achiral β,β-disubstituted and (Z)-β-monosubstituted Baylis-Hillman adducts with excellent Z/E stereospecificity in some cases. The process involves the conjugate additions of R2CuLi or RMgBr-CuBr-DMS to α,β-acetylenic esters and followed by additions of anionic α-(alkoxycarbonyl)vinyl]copper intermediates to aldehydes. The individual Z- and E- isomers of the resulting β-branched α-(hydroxylalkyl)acrylates can be separated by column chromatography in modest to excellent yield.

A new aminohalogenation process has been developed for the synthesis of vicinal haloamine derivatives using cinnamic esters as substrates. The reaction was performed in CH3CN using ZnCl2 or Cu(OTf)2 as catalyst and N,N-dichloro-p-toluenesulfonamide as chlorine/nitrogen source. Good to excellent yields and regio- and stereoselectivities have been obtained. The stereochemistry was unambiguously determined by transforming one of the products to a known sample.

Ytterbium(III) triflate has been found to catalyze anionic additions of functionalized lithium (α-carbalkoxyvinyl)cuprates to chiral p-toluenesulfinimines (thiooxime S-oxides) in a cosolvent system (Et2OCH2Cl2). This new system has made it possible to utilize those p-toluenesulfinimines of low solubility in Et2O as the electrophiles to react with anionic (α-carbalkoxyvinyl)cuprates for the asymmetric synthesis of the corresponding β-mono and β,β-disubstituted Baylis-Hillman adducts. Modest yields (51.0–64.4% yield) and good to excellent diastereoselectivities (> 90% de) were obtained.

A new anionic addition process has been developed for the asymmetric synthesis of unusual Baylis-Hillman adducts, β,β-disubstituted α-(hydroxyalkyl)acrylates. The new process involves conjugate addition of R 2 CuLi to β-substituted α,β-acetylenic ester to give lithium (α-carbalkoxyvinyl)cuprate which was then subjected to the carbonyl addition to aldehyde promoted by Et 2 AlCl. Modest to good diastereoselectivity (50.0 – 87.7 % de) has been obtained by using (1R,2S,5R)-(−)-menthol as the chiral auxiliary (59.0 – 94.0 % yield). The absolute configuration was unambiguously assigned by transforming the product to methyl (R)-α-methoxyphenylacetate.

A new method has been developed for the stereospecific synthesis of unusual ( Z )- β -branched Baylis-Hillman adducts with high Z E selectivity (>99 %) in modest to good yields. The process involves successful formation of anionic β-substituted [α-(alkoxycarbonyl)vinyl]aluminum intermediates and their coupling with aldehydes and ketones catalyzed by n -Bu 2 BOTf at −78 °C.

An efficient synthesis of N -(17 S -hydroxylinolenoyl)- l -glutamine (volicitin), a chemical elicitor from the herbivore-pest beet armyworm is presented. The synthesis, which utilizes a copper-catalyzed acetylene coupling, links ( S )-3,6-heptadiyne-2-ol with a C-8 propargylic iodine methyl ester to form the ( S )-17-hydroxylinolenate skeleton. By substituting different heptadiyne-2-ol groups, a series of methylene interrupted polyacetylene analogues were generated.

Ytterbium(III) triflate has been found to catalyze anionic additions of functionalized lithium (α-carbalkoxyvinyl)cuprates to chiral p-toluenesulfinimines (thiooxime S-oxides) in a cosolvent system (Et2OCH2Cl2). This new system has made it possible to utilize those p-toluenesulfinimines of low solubility in Et2O as the electrophiles to react with anionic (α-carbalkoxyvinyl)cuprates for the asymmetric synthesis of the corresponding β-mono and β,β-disubstituted Baylis-Hillman adducts. Modest yields (51.0–64.4% yield) and good to excellent diastereoselectivities (> 90% de) were obtained.

Some hindered chiral 1, 3-diketones were successfully synthesized from the reaction of (+)-3α-bromocamphor with acyl chlorides in the presence of samarium diiodide (SmI2) under mild reaction conditions in high yields.

TiCl4-Mediated Baylis–Hillman and aldol reactions were developed without the direct use of a Lewis base. These processes involve the conjugate addition of TiCl4 to α,β-unsaturated substrates followed by carbonyl coupling. Baylis–Hillman olefins were obtained when α,β-unsaturated ketones were employed as the substrates, whereas β-halogenated aldol products were generated with an α,β-unsaturated N-acyl benzoxalinone as the Michael-type acceptor.

An efficient deprotection of N - p -toluenesulfinyl group of β-branched Baylis–Hillman adducts has been developed by using Amberlite IR-120 (plus) ion-exchange resin in methanol solution at room temperature. Good to quantitative yields have been obtained for six examples. No racemization was detected under the mild conditions. This new method provides a simultaneous deprotection/purification, which has the great advantage over the solution phase deprotection technique of simplicity of work-up.

The asymmetric catalytic aldol reaction of silyl allenolates with aldehydes has been achieved by using N-C(3)F(7)CO oxazaborolidine as the catalyst. The fluoroacyl group of the catalyst was found to be crucial for control of enantioselectivity. The reaction provides the first enantioselective approach to beta-halo Baylis-Hillman-type adducts.

Transition metal–ligand complex-catalyzed regio- and stereoselective aminohalogenation of cinnamic esters has been developed using p-TsNCl2 as the nitrogen and chlorine sources. Dichloro-(1,10-phenanthroline)-palladium (II) as the catalyst can be handled very conveniently due to its property of less hygroscopic as compared with other aminohalogenation catalysts. The reaction is suggested to proceed through the mechanism involving N-tosyl N-chloro aziridinium intermediate. Eight examples are presented with modest to good yields (56–82%) and excellent stereoselectivity (>10:1).

N-Chloro-N-sodium-sulfonamide was found to react with olefins in the presence of copper catalyst to give vicinal haloamine derivatives instead of aziridines. The resulting regio and stereochemistry indicates that this unexpected reaction could proceed through the formation of unprecedented N-chloro-N-copper-2-nitrobenzenesulfonyl aziridinium intermediates, which can increase the successful chance to render the asymmetric version of the aminohalogenation reaction. In addition, this finding provides a more convenient protocol by the use of solely pure NsNClNa for the aminohalogenation reaction as compared to the mixed nitrogen and chlorine sources consisting of NsNCl2 and NsNHNa as previously reported by us. Two new simple olefin substrates, trans-stilbene and styrene, were also found to be effective for this new reaction system.

A substoichiometric amount of titanium tetrachloride was found to be effective to promote and participate in the tandem α-hydroxyalkylation/β-chlorination of α,β-acetylenic ketones in the presence of (n-Bu)4NI. This method provides the concise synthesis of (E)-β-halo Baylis–Hillman adducts. No β-iodo products were detected when using this combination of halogen sources. The reaction process involves 1,4-addition of chloro anion released from TiCl4 onto α,β-acetylenic ketones to give TiCl3–allenolate intermediates followed by the titanium Lewis acid-promoted carbonyl addition. Modest to good yields (53–77%) and excellent E/Z stereoselectivity (>95%) have been obtained for 10 examples.