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An organocatalytic enantioselective reaction of 2-methylcyclopentane-1,3-dione, nitroalkene, and α,β-unsaturated aldehyde with the diphenylprolinol catalyst was developed to give the highly functionalized Hajos–Parrish-type ketones with five to six contiguous stereocenters and two quaternary carbon stereogenic centers with high diastereoselectivity and enantioselectivity. The structures of the adducts were unambiguously confirmed by single-crystal X-ray crystallographic analyses of the appropriate products.

An efficient method has been developed for the enantioselective synthesis of tetrahydro-1H-pyrrolizin-3(2H)-ones starting from α,β-unsaturated aldehydes via a sequence of asymmetric Michael–oxidative esterification–Michal–reduction–reductive amination–lactamization reactions with high enantioselectivities (93–97% ee). The six-step reaction sequence can be conducted with the pot-economy synthetic strategy with only a one-step purification. The structure and absolute stereochemistry of the intermediates and products were confirmed by X-ray analyses of appropriate products.

A one-pot enantioselective synthesis of 7-azaindole-octahydroisoquinolin-3-one and an inside-aza-yohimbane system containing five contiguous stereogenic centers with high enantioselectivities (>99% ee) was achieved. The prepared highly functionalized polycyclic system provides a model for probing the solvent catalyzed proton transfer reaction and mimicking the local environment of the tryptophan moiety in proteins.

A series of nitrones (III) is readily prepared by a photocatalytic reaction of nitro compounds (I) with aldehydes (II) in the presence of iBu-N(iPr)2 as base.

A cascade organocatalysis has been developed for the enantioselective synthesis of a highly functionalized hexahydrophenanthrene-2-carbaldehyde containing five contiguous stereogenic centers with high diastereoselectivity and high enantioselectivity (>99% ee). The one-pot method comprises a cascade of organocatalytic Michael–Michael–Michael–aldol reactions of 2-methyl-1,5-dinitro-3-((E)-2-nitrovinyl)benzene and α,β-unsaturated aldehydes (e.g., cinnamaldehyde). The structure and absolute configuration of a product were confirmed by X-ray analysis of an appropriate derivative.

A double Michael reaction of the α,β-unsaturated aldehyde (I) with the unsaturated ketones produces a diastereomeric mixture of bicyclic nitroketones (III), which can be converted by subsequent Aldol/Henry reaction cascade to steroid type products (IV) in a one-pot manner.

Reaction of bromoacrylate (I) with cinnamic aldehyde (II) in the presence of diphenylsilylprolinol is optimized to yield a dialdehyde (III) produced by double Michael reaction.

A new method has been developed for the enantioselective synthesis of highly functionalized cyclohepta[b]indoles with high enantioselectivity (up to 96% ee). The process combines an enantioselective organocatalytic Michael addition and a highly efficient double Friedel–Crafts reaction sequence in one pot with good yields and stereoselectivity. The structures and absolute configurations of the products were confirmed by X-ray analysis.

In the presence of DBU and the prolinol derivative, unsaturated aldehydes undergo asymmetric anti-selective Michael addition to malonates of type (VI).

Formal [3 + 2]cycloaddition of 4-hydroxybut-2-enal, a succinaldehyde surrogate, with nitroalkenes in the presence of Jorgensen—Hayashi catalyst provides cyclopentanecarbaldehydes containing 4 consecutive stereogenic centers with excellent enantioselectivities.

Natural lignan (+)-galbulin (IV) is prepared via organocatalytic double Michael reaction of aldehyde (I) with ketoaldehyde (II) and a subsequent TosOH-promoted intramolecular aldol condensation as key steps.

A synthesis of fully substituted cyclopentanes bearing a quaternary carbon center and five contiguous stereogenic centers has been achieved by sequential organocatalyzed Stetter and Michael−Aldol reactions of heteroaromatic aldehydes, nitroalkenes, and α,β-unsaturated aldehydes via the [1 + 2 + 2] annulation strategy with dynamic kinetic asymmetric transformation and excellent enantioselectivities (up to >99% ee).

Synthesis of metal-butyrolactones via insertion of a metal acyl bond into an organic ketone is demonstrated, and the crystal structure of one example is reported; labelling experiments exclude the possibility that this insertion is initiated by intramolecular attack of the enol on the acyl group.

Tungsten-η4-carboxylated-1,3-diene cations in both s-trans and s-cis forms have been prepared and the influence of the diene conformation on its nucleophilic regiochemistry is demonstrated; the synthetic utility of these diene complexes is reported, and the crystal structure of one product has been determined.

Spiropyrazolines are obtained from the the tandem reactions of one molecular of azide and three molecules of alkyl vinyl ketone. There are two types of structures in these products: One of them has an intramolecular hydrogen bond the hydroxyl proton and the acetyl oxygen, while the other has none.

Reactions of acetonide derivatives of glucose, allose, galactose and fructose with MeMgI in benzene under reflux afford the corresponding monosaccharide derivatives having only one free hydroxy group in moderate to good yield.

The synthesis of spiro[4.4]nonane-1,6-diols via the catalytic as well as stoichiometric hydrogenation of spiro[4.4]nonane-1,6-dione was studied. Profound effects of the hydrogenation catalysts and reagents on the stereoselectivity of the products were observed. The choice of solvent also was found to have a significant influence on the product selectivity. The opening of a spiro-ring in the starting material was identified as a major side reaction in alcohol solvents. The absolute configuration of the trans, trans-diol was unambiguously determined by X-ray crystallography.

Metal carbonyl salts CpW(CO)3Na, Re(CO)5Na, and CpFe(CO)2Na were used for intramolecular cyclization of 1-(3-bromo-1-propynyl)-2-(3-oxopropyl)benzene. Among these salts, CpW(CO)3Na was found to be ...

Facile deprotonation of a number of cationic ruthenium vinylidene complexes, followed by cyclopropenation, is accomplished in acetone. The deprotonation of [Ru]C(Ph)CH2R+, ([Ru] = (η5-C5H5)(PPh3)2Ru) by n-Bu4NOH induces a novel cyclization reaction and yields the neutral cyclopropenyl complexes [Ru]−CC(Ph)CHR (3b, R = CN; 3c, R = Ph; 3d, R = CHCH2; 3e, R = CHCMe2). Complex [Ru]−CC(C6H9)CHCN+ (3k) is similarly prepared. Protonation of 3b−3e regenerates the corresponding vinylidene complexes. Deprotonation of [Ru]CC(Ph)CH2COOMe+ (2h) by n-Bu4NOH induces a different type of cyclization and yields the neutral furan complex [Ru]−CC(Ph)CHC(O)OMe (4h). The cyclopropenyl complex containing a methoxy substituent cannot be prepared from [Ru]CC(Ph)CH2OCH3+ (2i), but F- of n-Bu4NF attacks the Cα of 2i to produce the unstable vinyl complex [Ru]C(F)C(Ph)CH2OCH3 (5). Complex [Ru]−CC(Ph)C(CN)OCH3 (9b) was indirectly prepared from the addition of TCNQ to 3b, giving [Ru]CC(Ph)CH(CN)TCNQ (6b) followed by methanolysis. Unlik...

Reactions of ortho esters of myo-inositol 8 or 10 with 1−2 equiv of Grignard reagents in benzene−ether yield regio- and stereoselectively the corresponding ring opening products having a free hydroxy group at C-1. The regioselectivity is rationalized owing to the presence of the 2-methoxy group which will serve as an auxiliary to form a chelation complex 12 with magnesium. Inositol derivatives having two free hydroxy group at C-1 and C-3 positions can be achieved from reactions of 6 or 8 with excess Grignard reagents or under more drastic conditions. The reaction of 8b with excess LiAlH4/AlCl3, on the other hand, yields the corresponding 1,5-diol 19.

The applications of 1,4-di-O-tert-alkyl-l-threitols as chiral auxiliaries in the asymmetric nucleophilic addition of alkyllithiums to hydrazones are investigated. Chiral acetal-hydrazones 9, obtained from the chiral acetals 8 by ozonolysis followed by treatment with dimethylhydrazine, are allowed to react with organolithium reagents in toluene at − 78 °C to give 15 with excellent diastereoselectivity. The stereochemical assignments were based on the X-ray crystal structure of 17a. The absolute configuration at C2 of the major isomer of the adducts 15 was thereby determined to be S. The nucleophile thus attacked from the si face of the CN moiety. The effect of solvent on the diastereoselectivity of the reactions of 9 with organolithium reagents is reported. Polar aprotic solvent shows poor diastereoselectivity, and the diastereoselectivity is reversed when the reaction is carried out in THF. Reaction of dl-14 with methyllithium has been studied for comparison purposes and the reaction shows the opposite se...

The reaction of diethyl 2,2‘-diiodo-4,4‘-biphenyldicarboxylate (7) with diarylacetylenes in the presence of 3,5-(NO2)2C6H3CO2Me (MeDNB) or 4-(NO2)C6H4CO2Me (MePNB), Pd(OAc)2 (10 mol %), K2CO3, and Bu4NBr, in DMF at 100 °C, gives 4-methyl-9,10-diaryl-2,7-phenanthrenedicarboxylic acid diethyl esters in good yields. The methyl group at position 4 originates from the electron-deficient methyl nitrobenzoates. High regioselectivity for the annulation of 7 with nonsymmetrical diarylalkynes was observed with the selectivity controlled mainly by electronic factors rather than by steric factors. A competitive kinetic isotope study was carried out using a 1:1 mixture of MePNB and MePNB-d3 in the annulation reaction of 7 which gave 4-methyl- and 4-(methyl-d3)phenanthrene in a 67:33 ratio, leading to an apparent value of kH/kD = 1.26. Possible mechanisms for the methyl transferring process are discussed.

1,3-Dipolar cycloadditions of upper- and lower-rim diallylcalix[4]arenes (1 and 3) with aryl dinitrile oxides provide a unique and efficient way of capping the calix[4]arenes. When dinitrile oxides reacted with 5-allylcalix[4]arene 7, they underwent a 1,3-dipolar cycloaddition on one side and an electrophilic substitution on the other side, which led to a novel type of asymmetric calix[4]arenes (9 and 12).

[reaction: see text] In contrast to the [3+2] or [4+3] cycloaddition of N-metalated azomethine ylides and various alkenes, N-benzylidene glycine ethyl ester reacts with fulvenes to give the hetero [6+3] cycloaddition adducts with high stereoselectivity, constituting an efficient and novel route to [2]pyrindines.

The reaction between [Cr(bdmpam)(CO)3][bdmpam = bis(3,5-dimethylpyrazol-1-ylmethyl)-aminomethane] and an excess of [NO][BF4] in MeCN gives the air-stable 17-electron monomeric product [Cr(bdmpam)(NO)(NCMe)2][BF4]2, which has been characterized by elemental analysis, i.r., e.s.r. spectroscopy, magnetic moment, and X-ray crystallography. The observed air stability of this paramagnetic monomer can be attributed to the presence of the bulky multidentate ligand bdmpam.

The pentanuclear heterometallic acetylide complex Cp 2 Mo 2 Ru 3 (CO) 10 (CCPh) 2 ( 3 ) was prepared by the reaction of the metal acetylide CpMo(CO) 3 CCPh with Ru 3 (CO) 12 . This complex was characterized by spectroscopic methods and by X-ray single-crystal structure determination. Notable structural features of the new complex 3 include an unusual symmetric pentametallic double butterfly skeleton and a novel μ 4 -η 2 bonding mode for the acetylide ligand. Crystal data for 3 : space group P 2 1 / c ; a 24.119(10), b 20.739(4), c 15.358(3) A, β 101.68(4)°, Z = 8; final R = 0.038, R w = 0.034 and GOF = 1.57.

Reaction of the transition metal pentadienyls (I) with tetracyanoethylene (II) results in the formation of the (4 + 2) (III) or (3 + 2)cycloadducts (IV).