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To stabilize S

A new efficient metal-based frustrated Lewis pair constructed by (Pt Bu3 )2 Pt and B(C6 F5 )3 was designed through density functional theory calculations for the catalytic dehydrogenation of ammonia borane (AB). The reaction was composed by the successive dehydrogenation of AB and H2 liberation, which occurs through the cooperative functions of the Pt(0) center and the B(C6 F5 )3 moiety. Two equivalents of H2 were predicted to be liberated from each AB molecule. The generation of the second H2 is the rate-determining step, with a Gibbs energy barrier and reaction energy of 27.4 and 12.8 kcal/mol, respectively.

Heteroatomic derivatives of Chichibabin's hydrocarbon are explored theoretically to highlight the relationship between the electronic structure and nonlinear optical (NLO) properties. The results show that the systems are divided into two classes: one that has intermediate electronic structure between two main contributing resonance structures, and a second with an electronic structure that is approximated by only one resonance structure. It is found that the former class of derivatives exhibits approximately one-order larger static second hyperpolarizability (γ) than the latter class, because of either their intermediate diradical or charge-transfer (CT) characteristics. The asymmetric systems are further scrutinized by using the static electric field model, which shows that the intermediate CT character is essential for the very large enhancement of γ in the asymmetric systems. These results not only clarify the structure–property relationships of open-shell singlet NLO compounds with redox switching properties, but also shed light on a new and unexplored class of closed-shell NLO systems generated by the introduction of intermediate CT nature into open-shell singlet systems.

A new pentacene-type silaborin, in which three benzene rings are bridged by silicon and boron atoms, has been synthesized and characterized by using NMR spectroscopy and X-ray crystallographic analysis. The precursor, 1,4-bis(dimesitylboryl)-2,5-bis(phenylsilyl)benzene (4), was prepared by stepwise introduction of a silyl group and a boryl group to a benzene ring starting from 1,4-dibromobenzene. Double cyclization of 4 proceeds by a H-Mes exchange and a B-H/C-H dehydrogenative condensation to afford pentacene-type silaborin 5. X-ray crystal structure analysis reveals that 5 adopts a bent structure rather than a planar one. UV/Vis spectra and DFT calculations for 5 reveal a lowering of the LUMO energy level compared with corresponding anthracene-type 3.

A method for the introduction of various substituents at the 4 and 8 positions of 2,10-di-tert-butyldipyrido[1,2-c;2′,1′-e]imidazolium salts, is described. The new imidazolium salts bearing substituents (R′ = Cl, SPh) at the 4 and 8 positions are synthesized in three-step procedures, and carbenes generated from the imidazolium salts can be used to give the corresponding rhodium complexes. The role of the 4,8-substituents can be either bystanders or coordinating ligands according to the nature of the metal moiety.

The isolation and study of carbenes with σ-donating and π-accepting properties stronger than those of N-heterocyclic carbenes (NHCs) have been regarded as one of the big challenges in carbene chemistry. We have investigated the properties of 1,8-disubstituted xanthylidene-based compounds by using two different approaches: The photolysis-induced formation of free carbenes and the synthesis of the corresponding metal–carbene complexes by oxidative addition. The former study revealed that the carbene unsubstituted at the 1- and 8-positions is kinetically more reactive than the parent xanthylidene and that the substituents at the 1- and 8-positions are less effective in generating carbenes by photolysis. However, oxidative addition of palladium(0) to the 1,8-diphenyl-substituted precursor successfully afforded a low-coordinate 14-electron palladium(II)–carbene complex. This unusual complex is stabilized by agnostic interactions involving an adjacent phenyl group. This complex is the second example of a stable cationic 14-electron palladium(II)–carbene complex to have been reported so far.

New allene compounds, 5c and 5d, bearing 1,8-dichloroacridene moieties were synthesized, and the oxidation of 5c and 5d was performed to generate thermally stable triplet carbenes. Since the oxidation resulted in the formation of decomposition products, the photolysis of brominated allene compound 18 was performed. UV–vis measurement at low temperatures indicated the generation of intermediates with decreasing starting material 18, although the efficiency of photolysis was quite low. ESR and electron spin transient nutation (ESTN) spectra suggested that the multiplicity of intermediates is triplet, probably the target triplet carbene 6d is generated. In terms of |D| values of the intermediates, ESR showed that unpaired electrons are more effectively delocalized in 6d by the introduction of nitrogen atoms in the skeleton (biradical character in Scheme 1). The observed triplet species 6d was not stable enough to isolate. Copyright © 2014 John Wiley & Sons, Ltd.

A bit borane: Silicon-functionalized dibenzosilaborins were prepared by intramolecular B-H/C-H dehydrogenative cyclization of o-(silyl)(hydroboryl)benzenes. The hydrosilyl derivative (X=H) can be converted into the fluorosilane (X=F) and chlorosilane (X=Cl). UV/Vis and fluorescence spectra are influenced by the functional groups X on the silicon atom through σ*-π* conjugation.

The countercation effect on the reactivity of ambiphilic o-(fluorodimethylsilyl)phenyl anion was investigated by replacing Li in 1 with Cu (4 and 5), Mg (6), and Zn (7). The reactivity of the aryl metal species was estimated by the yields of dimerized product 3, which were monitored by GC. X-ray crystallographic analysis, DFT calculations, and AIM analysis of bis(aryl)zinc 7 were performed. © 2012 Wiley Periodicals, Inc. Heteroatom Chem 24:53–57, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/hc.21062

o-C(6)H(4)(SiR(3-n)H(n))(BMes(2)) (1; R=Me, Ph; n=1, 2) undergo Mes-H (Mes=mesityl) ligand exchange between the silicon atom and the boron atom to form o-C(6)H(4)(SiMesR(3-n)H(n-1))(BMesH) (6) upon heating. The resulting hydroborane intermediates (6) immediately react with benzaldehyde to afford their corresponding benzyloxyboranes (5). A DFT study of model compounds reveals the transition states of the ligand exchange. A hydride abstraction from the silicon atom by the boron center is key to reaching the transition states, which include the tricoordinate silyl-cation moiety and the tetracoordinate hydridoborate moiety.

Computational analysis on the dicationic species generated upon two-electron oxidation of the corresponding allenic compounds bearing two thioxanthene (7a) or two acridene (7b) moieties indicated that the ground-state multiplicity would be of the triplet state (ΔEST = ECS − ET = 12.6 and 14 kcal/mol, respectively). Under this premise, oxidation reactions of 7a and 7b were carried out. In the case of 7b, oxidation with (p-BrC6H4)3N•+SbCl6− gave a dimer (13), which could be presumed to have formed by dimerization of the corresponding carbene. Oxidation of 7b in the presence of tetramethylpiperidine N-oxide afforded the corresponding ketone derivative (14), thus implying the likelihood of a triplet carbene being the reactive intermediate. These results suggest that double oxidation of heterocyclic allene compounds is viable as a new approach for generating triplet carbenes. Copyright © 2011 John Wiley & Sons, Ltd.

A series of the monocyclic organophosphorus compounds ([o-OC(CH3)2C6H4]PPh(CH2 Ph)X) bearing a halogen (X = F, Cl, and Br) or a tetrafluoroborate (X = BF4) were synthesized. The solid-state structures of the bromide, the tetrafluoroborate, and an analogous fluoride ([o-OC(CF3)2C6H4]PPh(CH2 Ph)F) were determined by single crystal X-ray crystallography. The geometry of the fluoride was almost an ideal trigonal bipyramid (TBP). On the other hand, the bromide and tetrafluoroborate were essentially phosphonium salts with phosphorane character to some extent for the former. In CD3 CN, the bromide, the chloride, and the tetrafluoroborate were found to exist as phosphonium salts. However, it was suggested that in CDCl3, the bromide and the chloride have structures rapidly equilibrating or averaged between the phosphorane and the phosphonium forms. © 2011 Wiley Periodicals, Inc. Heteroatom Chem 22:523–530, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/hc.20717

Reactions of o-(HSiR2)(BMes2)C6H4 (R = Me (3a), Ph (3b)) with a fluoride ion afford [o-(FSiR2)(HBMes2)C6H4]− (R = Me (5a), Ph (5b)), which involve the FSi⋅⋅⋅HB interaction to render the silicon atom pentacoordinate. The FSi⋅⋅⋅HB interaction in 5a was confirmed by X-ray crystallographic analysis and “atoms-in-molecules” (AIM) analysis. © 2011 Wiley Periodicals, Inc. Heteroatom Chem 22:471–475, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/hc.20709

Neutral hexacoordinate organoantimony compounds LSb(Xyl)C6H4 (o-Y) [L = tridentate ligand; Xyl = C6H3 (3,5-Me2); Y = CH2 OMe (4), CH2 NMe2 (5), and 2-pyridyl (6)] with intramolecular coordination were synthesized. Single crystal X-ray crystallography revealed that the donor atom (N or O) of 4–6 was coordinated trans to one of the two carbon atoms of the tridentate ligand. Variable temperature (VT) NMR measurements of compounds 4 and 5 indicated that the stereomutations proceeded via dissociation of the Sb-donor (N or O) bond followed by SbC bond rotation. Compound 4 was found to have a stereomutation barrier of ca. 12 kcal mol−1. In the case of 5, dissociation of the SbN bond was found to be distinguishable from the stereomutation. Energies of SbN dissociation 5 and interconversion of enantiomers were estimated to be ca. 15 and ca. 19 kcal mol−1, respectively, from the VT-NMR measurements. © 2011 Wiley Periodicals, Inc. Heteroatom Chem 22:553–561, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/hc.20721

A novel bidentate ligand based on 1,1,1,3,3,4,4,4-octafluoro-2-phenyl-2-butanol (16) has been used to synthesize a diastereomeric pair of hydrophosphoranes (18-exo and 18-endo). A comparison of the structures of a series of hydrophosphoranes (18-exo, 18-endo, 19, and 20-exo) obtained by X-ray crystallography indicated that the apical P–O bond lengths were affected by the electronic properties of the oxygen atom, which can be interpreted by the “single bond/no bond resonance” concept. From the hydrophosphoranes, O-apical (13-exo and 13-endo) and anti-apicophilic O-equatorial (12-exo and 12-endo) phosphoranes were synthesized. The O-equatorial phosphoranes were irreversibly converted into diastereomeric pairs of O-apical isomers. Kinetic measurements implied that the electronic properties of the pentafluoroethyl group are comparable to those of the trifluoromethyl group. The activation enthalpies calculated for the stereomutations enabled us for the first time to experimentally show the stability of an O-apical isomer to be greater than that of an O-equatorial isomer by 13.7 kcal mol–1.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

1,1,1,2,2,4,4,5,5,5-Decafluoro-3-phenyl-3-pentanol (13) was prepared via the Cannizzaro-type disproportionation reaction, and dimetallated 13 (i.e., 15) was used as a bidentate ligand, which was bulkier than the Martin ligand (1,1,1,3,3,3-hexafluoro-2-phenyl-2-propanol). P-H spirophosphorane (16) was synthesized utilizing the new bidentate ligand, and the structure of 16 was essentially the same as that of the P-H phosphorane with the Martin ligands (1b). Phosphoranes which exhibit reversed apicophilicity (9: O-equatorial) were also synthesized and could be converted to the corresponding stable stereoisomers (10: O-apical). The crystal structures of O-equatorial phosphoranes (9) and those of O-apical isomers (10) were slightly affected by the steric repulsion of pentafluoroethyl groups. Kinetic measurements revealed that the stereomutation of O-equatorial methylphosphorane (9a) to the O-apical isomer (10a) was slowed. The activation enthalpy for the stereomutation of 9a→10a (24.4 kcal mol–1) was higher than that of the phosphorane bearing the Martin ligands (3a→4a: 19.3 kcal mol–1) by 5.1 kcal mol–1.

Hypervalent bond (three center-four electron bond: 3c-4e) is the central feature of the structure and reactivity of hypervalent compounds. The SSS bond of thiathiophthene, the so-called no-bond resonance compound, is realized as one of the examples of 3c-4e bond centered at the sulfur atom (10-S-3). A variety of reactions such as cycloaddition-elimination, bond-switching rearrangement, and bond-switching equilibration of sulfur-containing heterocycles are exemplified to proceed through the presence of hypervalent 10-S-3 species. In the transition state of edge inversion, it is predicted that a vacant p-type orbital is perpendicular to the square planar species. Antimony(III) and bismuth(III) compounds bearing a bidentate Martin ligand and a phenyl, or 2-dimethylaminomethylphenyl, or 2,6-bis(dimethylaminomethyl)phenyl group were prepared. The rates of inversion of these compounds at the central atom of Sb or Bi were accelerated significantly by the coordination of the dimethylamino group and also of pyridine from the solvent, where 3c-4e bond is formed by the coordination to stabilize the transition state. Finally, the presence of rapid bond-switching equilibration between NB···N bond of 1,8-bis(dimethylamino)-9-(substituted)borylanthracenes was shown to proceed through 10-B-5 species at the transition state. It is concluded that the bond-switching equilibration takes place as a piston rod in the range of 1.32 A. © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:161–175, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20326

A variety of hexaorganotellurium compounds, Ar6−n(CH3)nTe [Ar=4-CF3C6H4, n=0 (1 a), n=1 (3 a), n=2 (trans-4 a and cis-4 a), n=3 (mer-5 a), n=4 (trans-6 a); Ph, n=0 (1 b), n=1 (3 b), n=2 (trans-4 b); 4-CH3C6H4, n=0 (1 c), n=1 (3 c), n=2 (trans-4 c), n=4 (trans-6 c); 4-BrC6H4, n=0 (1 d)] and Ar5(R)Te [Ar=4-CF3C6H4, R=4-CH3OC6H4 (8); Ar=4-CF3C6H4, R=vinyl (9), Ar=Ph, R=vinyl (10), Ar=4-CF3C6H4, R=PhSCH2 (11), Ar=Ph, R=PhSCH2 (12), Ar=4-CF3C6H4, R=nBu (13)] and pentaorganotellurium halides, Ar5TeX [Ar=4-CF3C6H4, X=Cl (2 a-Cl), X=Br (2 a-Br); Ar=Ph, X=Cl (2 b-Cl), X=Br (2 b-Br); Ar=4-CH3C6H4, X=Cl (2 c-Cl), X=Br (2 c-Br); Ar=4-BrC6H4, X=Br (2 d-Br)] and (4-CF3C6H4)4(CH3)TeX [X=Cl (trans-7 a-Cl) and X=Br (trans-7 a-Br)] were synthesized by the following methods: 1) one-pot synthesis of 1 a, 2) the reaction of SO2Cl2 or Br2 with Ar5Te−Li+ generated from TeCl4 or TeBr4 with five equivalents of ArLi, 3) reductive cleavage of Ar6−m(CH3)mTe (m=0 or 2) with KC8 followed by treatment with CH3I, 4) valence expansion reaction from low-valent tellurium compounds by treatment with KC8 followed by reaction with CH3I, 5) nucleophilic substitution of Ar6−y−z(CH3)zTeXy−z (X=Cl, Br, OTf; z=0, 1; y=1, 2) with organolithium reagents. The scope and limitations and some details for each method are discussed and electrophilic halogenation of the hexaorganotellurium compounds is also described.

The enantiomers of the first optically active selenurane oxide ever reported, C2-symmetric 3,3,3′,3′-tetramethyl-1,1′-spirobi[3h,2,1]-benzoxaselenole oxide, were isolated via enantioselective liquid chromatography of the racemate or by spontaneous resolution that occurs during the slow evaporation of its acetonitrile solution or the slow crystallization from the same solvent. Chirality 16:598–601, 2004. © 2004 Wiley-Liss, Inc.

By freezing Berry pseudorotation of spirophosphoranes with recourse to the rigidity of the Martin bidentate ligand, we successfully prepared configurationally stable enantiomeric pairs of optically active phosphoranes, and could isolate “anti-apicophilic” C-apical O-equatorial (O-cis) phosphoranes. The effect of σ*PO orbital of the O-cis phosphorane was investigated both experimentally and theoretically. O-cis phosphoranes were revealed to be much more electrophilic at the phosphorus atom than O-trans isomers by experimental studies. The acidity of the α-proton of an O-cis benzylphosphorane was found to be higher than that of the corresponding O-trans isomer. By the reaction of the α-carbanion of an O-cis benzylphosphorane with PhCHO, we succeeded in the first isolation and full structural characterization of a 12-P-6 phosphate bearing an oxaphosphetane ring, the intermediate in the Wittig type reaction using a 10-P-5 phosphorane. © 2002 Wiley Periodicals, Inc. Heteroatom Chem 13:390–396, 2002; Published online in Wiley Interscience (www.interscience.wiley.com). DOI 10.1002/hc.10072

The reaction of cyclopentane and cyclohexane carboxylates with cis-pentenals (II) proceeds in the presence of a fluorinated cosolvent to afford the corresponding furan products with high diastereoselectivity.

A bit borane: Silicon-functionalized dibenzosilaborins were prepared by intramolecular B-H/C-H dehydrogenative cyclization of o-(silyl)(hydroboryl)benzenes. The hydrosilyl derivative (X=H) can be converted into the fluorosilane (X=F) and chlorosilane (X=Cl). UV/Vis and fluorescence spectra are influenced by the functional groups X on the silicon atom through σ*-π* conjugation.

Hypervalent 10-Sn-5 allyl and crotyl tin ate complexes bearing Martin ligands were prepared and found to be surprisingly stable in water. These compounds were found to react with aldehydes in the presence of weak Lewis acids such as LiBr to give the corresponding homoallyl alcohols. Product analysis of the reaction of the crotyl compounds indicated that the reaction occurred via a cyclic transition state unlike an acyclic transition state operative for widely utilized allyltrialkyltin reagents that are of ordinary valency. © 2001 John Wiley & Sons, Inc. Heteroatom Chem 12:425–430, 2001

[(Por)M(R)(OOR′)]+Y− (Por: TPP [tetraphenylporphyrin], OEP [octaethylporphyrin]; M: Sb, As, P; R: Me, Et, Ph; R′: H, C(=O)m-ClC6H4, t-Bu) were prepared from [(Por)M(R)(X)]+Y− (X: OTf, Br). The reactivities of the peroxide porphyrins toward nucleophiles such as triphenylphosphine increased in the order of -OOt-Bu, m-CPBA, and -OOH derivatives. Phosphorus (P-OOH) and arsenic hydroperoxide (As-OOH) were much more reactive than the corresponding antimony hydroperoxide (Sb-OOH). The higher reactivity of phosphorus and arsenic peroxides can be explained by the stability of the M=O (M=P, As) bonding system in the intermediates of the oxidation reactions. An X-ray structural analysis of [(TPP)Sb-(Me)(OOt-Bu)]+PF6− is presented. © 2001 John Wiley & Sons, Inc. Heteroatom Chem 12:431–443, 2001

In order to elucidate the electronic nature of our recently reported first hexacoordi- nated carbon (12-C-6), density functional theory (DFT) calculations of sulfide precursor, sul- fone derivative, and S + -F derivative were carried out and compared with those of the reported S + -Me hexacoordinated carbon. Computations on the hexacoordinated carbon, indicating that four attractive C-O interactions with the central hexacoordinate carbon atom exist, also revealed that the interactions consist of two different types of three-center four-electron bonds, which can be regarded as electron donation by the lone pairs of the oxygen atoms to the empty low-lying π*-orbitals of the allene. The optimized structures of the sulfide, sul- fone, S + -F, and the original S + -Me suggested that the introduction of electron-withdrawing groups at the sulfur atoms would make the C-O attractive interactions stronger by a larger contribution of the carbon dication resonance structure. Thus, allene compounds (sulfide, sulfone, sulfonium) with two different thioxanthene ligands (one with 1,8-dimethoxy groups as in the S + -Me compound and the other with 1,8-diphenoxy groups) were synthesized to confirm the predicted substituent effects on the C(central)-O interactions. Electron-withdrawing substituents at the sulfur atoms were found to give rise to strong C(central)-O attractive interactions; the average values of the four C-O distances were smaller as the electron-withdrawing ability of the sulfur atoms rose. Additionally, C(central)OMe distances were shorter than the corresponding C(cen- tral)OPh distances, reflecting the higher electron-donating ability of the oxygen atoms at these 1,8-positions of the thioxanthene skeleton.

Dithienostiboles having a stibole ring fused with a bithiophene system are prepared for the first time.

New allene compounds bearing 1,8-diphenoxy or bis(3,5-di-tert-butylphenyl) oxyacridene (diaryloxyacridene) moieties were synthesized. These compounds were more easily oxidized than Cl-substituted compounds. The allene compounds were oxidized to generate thermally stable triplet carbenes. Electron spin resonance and electron spin transient nutation spectra of the oxidation reaction products suggested the generation of triplet species; however, the main isolated product from the 1,8-diphenoxy allene was a cyclized compound that was characterized by X-ray analysis. The product derived from diaryloxy allene was also characterized by X-ray analysis as a singlet species, which included a vinyl cation stabilized by a neighboring O(3,5-di-tert-butylphenyl) group. This singlet species was stable even at room temperature and did not show any electron spin resonance signals in solution, indicating that the triplet species was not in equilibrium with the singlet. Copyright © 2016 John Wiley & Sons, Ltd.

A stable hypervalent 10-Bi-4 species, tetraethylammonium bis[α,α-bis(trifluoromethyl)benzenemethanolato(2-)-C2],Obismuthanate(1-), was prepared by the reaction of bismuth trichloride with 2 equiv of lithium 2-(2-lithiophenyl)-2-propoxide derivatives. The ate complex was inert toward MeI, instead, the corresponding nonfluorinated analogue, bis[α,α-bis(dimethyl)benzenemethanolato(2-)-C2, O]bismuthanate(1-), was reactive enough toward MeI to give O-methylated product. Regioselective methylation at the nonfluorinated methanolate was observed in the reaction of unsymmetrically substituted ate complex, [α,α-bis(dimethyl)benzenemethanolato(2-)-C2, O[]α,α-bis(trifluoromethyl) benzenemethanolato(2-)-C2, O]bis-muthanate(1-). Mechanism of isomerization of these ate complexes and related protonated compounds and the synthesis and stability of [α,α-bis(trifluoromethyl)-benzenemethanolato (2-) -C2, O]diarylbismuthanate-(1-) were also described.

The anionic 10-Bi-4 species ( 2a , 2b ) were synthesized by the reaction of BiCl 3 with 2 equiv of lithium 2-(2-lithiophenyl)-2-propoxide derivatives ( 1a , 1b ). The X-ray crystallographic analysis showed 2a- Et 4 N + to be distorted pseudotrigonal bipyramid in geometry. Reaction of dimethyl-substituted 2b- Li + with methyl iodide took place exclusively not at the bismuth but at the oxygen to give an ether 4 .

Novel cationic Lewis acids were generated by the addition of silver hexafluoroantimonate to titanium complexes 7 (TiCl4·(R,R)-1,2-diphenylethane-1,2-diol dialkyl ether) or 8 (TiCl3(OR)·(R,R)-1,2-diphenylethane-1,2-diol dialkyl ether) at −20 °C. Interestingly, the titanium complexes 7 or 8 could be isolated and the structures of 7c (TiCl4·(R,R)-1,2-diphenylethane-1,2-dioldi-n-propyl ether) and 8a (TiCl3(O-i-Pr)·(R,R)-1,2-diphenylethane-1,2-diol dimethyl ether) were determined by X-ray analysis. Asymmetric aldol reaction using the cationic Lewis acids is also described.

The synthesis of (S,S)-1,2-bis(3,5-di-tert-butylphenyl)ethane-1,2-diol (98.6% ee), which should be useful as a chiral ligand of catalysts in asymmetric inductions, is described.

[(Por)M(R)(OOR′)]+Y− (Por: TPP [tetraphenylporphyrin], OEP [octaethylporphyrin]; M: Sb, As, P; R: Me, Et, Ph; R′: H, C(=O)m-ClC6H4, t-Bu) were prepared from [(Por)M(R)(X)]+Y− (X: OTf, Br). The reactivities of the peroxide porphyrins toward nucleophiles such as triphenylphosphine increased in the order of -OOt-Bu, m-CPBA, and -OOH derivatives. Phosphorus (P-OOH) and arsenic hydroperoxide (As-OOH) were much more reactive than the corresponding antimony hydroperoxide (Sb-OOH). The higher reactivity of phosphorus and arsenic peroxides can be explained by the stability of the M=O (M=P, As) bonding system in the intermediates of the oxidation reactions. An X-ray structural analysis of [(TPP)Sb-(Me)(OOt-Bu)]+PF6− is presented. © 2001 John Wiley & Sons, Inc. Heteroatom Chem 12:431–443, 2001

Hypervalent 10-Sn-5 allyl and crotyl tin ate complexes bearing Martin ligands were prepared and found to be surprisingly stable in water. These compounds were found to react with aldehydes in the presence of weak Lewis acids such as LiBr to give the corresponding homoallyl alcohols. Product analysis of the reaction of the crotyl compounds indicated that the reaction occurred via a cyclic transition state unlike an acyclic transition state operative for widely utilized allyltrialkyltin reagents that are of ordinary valency. © 2001 John Wiley & Sons, Inc. Heteroatom Chem 12:425–430, 2001

In order to obtain a pentacoordinate hypervalent carbon compound with two strong apical bonds, a new compound bearing the novel skeleton 4 was synthesized by the two-electron oxidation of 9 followe...

o-[(Dimesitylboryl)phenyl]dimethylsilane (1a) undergoes dehydrogenative condensation with alcohols and amines, giving the corresponding alkoxysilanes 4–7 and aminosilanes 8 and 9 in moderate to hig...

Functional group transformations of 7-silabenzonorbornadiene derivatives have been investigated. The 7-mesityl-7-silanorbornadiene 1 was prepared and converted into the 7-chloro derivative 5. Reduc...