9 research outputs found
Trimethylsilyl chloride assisted conjugate addition-elimination of organocopper reagents to 2-bis(methylthio)nitroethylene: an efficient and highly stereoselective synthesis of 2-methylthio-2-alkyl/aryl-1-nitroethylenes and their application for synthesis of nitroheterocycles
An efficient method for the synthesis of novel 2-methylthio-2-alkyl/aryl-1-nitroethylenes 2 has been developed via conjugate addition-elimination of organocopper reagents to nitroketene dithioacetal 1 in the presence of TMSCl. The product nitroethylenes 2 have been further utilized for the synthesis of substituted 3-nitro-2-alkyl/arylpyrroles 5 by their reaction with aminoacetaldehyde dimethylacetal followed by acid catalyzed cyclization in ethereal HCl. The reaction of 2 with propargyl alcohol has also been investigated
Highly chemoselective and stereoselective conjugate addition of benzyl copper reagents to α-oxoketene dithioacetals
Benzyl copper reagents derived by transmetallation between benzylmagnesium chloride and Cu(I) species are shown to undergo conjugate addition - elimination with acyclic and cyclic α-oxoketene dithioacetals to afford the corresponding β-benzyl vinylogous thiolesters in highly stereo- and chemoselective manner
Highly regioselective 1,2-addition of alkoxybenzyl Grignard reagents to α-oxoketene dithioacetals: a facile regiocontrolled synthesis of alkoxynaphthalenes and their condensed analogs via aromatic annelation
4-Methoxybenzyl- (A), 3,4-dimethoxybenzyl- (B) and 3,4-methylenedioxybenzyl- (C) Grignard reagents are shown to undergo regioselective 1,2-addition with various acyclic and cyclic -oxoketene dithioacetals to afford carbinol dithioacetals which on BF3.Et2O catalyzed cyclization yield alkoxynaphthalenes and their condensed derivatives in a highly regiocontrolled manner
Highly efficient and selective displacement of alkylthio group on acylketene O,S-acetals by organocopper reagents: a novel route to 2-alkoxy/aryloxy-1-alkenylketones
Acylketene O,S-acetals 1a-k undergo efficient and selective conjugate displacement of alkylthio group with organocopper(l) reagents to afford the corresponding 6-alkoxy/aryloxy enones 2-21 in good yields