Addition of Organolithium Reagents to Some Carbohydrate Enones
作者:Osman Achmatowicz、Barbara Szechner、Jan K. Maurin
DOI:10.1016/s0040-4020(97)00253-6
日期:1997.4
Addition of organolithiumreagents to the sugar enones: alkyl 2,3,6-trideoxy-α-l- and 2,3-dideoxy-α-d-hex-2-enopyranosid-4-ulose has been examined. Butyl, benzyl and 2,5-dimethoxy-4-methylphenyllithium add, with increasing stereoselectivity, to the carbonyl group of the α,β-unsaturated ketosugars, whereas 2,5-dimethoxybenzyllithium undergoes stereospecific conjugate addition and 1,2-addition in the
Serial Radical Reactions of Glycals: Ready Routes to Highly Functionalized C-Glycosyl Derivatives
作者:J. Cristobal Lopez、Ana M. Gomez、Bert Fraser-Reid
DOI:10.1021/jo00117a044
日期:1995.6
The C3-OH of partially protected glycals can be readily converted into mixed acetals of 2-bromoacetaldehyde or into silylmethylene bromides. Reaction of these derivatives with tri-n-butyltin hydride gives a radical that cyclizes efficiently to generate a stabilized radical at C1. The latter can be trapped very efficiently with acrylonitrile, tert-butyl isocyanide, allyltri-n-butyltin, tributyltin acrylates, or a complex pyranoside enone to afford C-glycosides in which a 1,2 disubstitution has taken place. The stereochemistry of the resulting 1,2 disubstituted product is dependent, at C-2, on the stereochemistry of the C3-OH and at the anomeric center (C-1) upon the interplay of (a) steric effects and (b) the electronic bias of the radical anomeric effect.
Serial radical reactions of enol ethers: ready routes to highly functionalized C-glycosyl derivatives
作者:J. Cristobal Lopez、Bert Fraser-Reid
DOI:10.1021/ja00191a064
日期:1989.4
Rao, B. Venkateswara; Chan, J. B.; Moskowitz, N., Bulletin de la Societe Chimique de France, 1993, vol. 130, # 3, p. 428 - 432
作者:Rao, B. Venkateswara、Chan, J. B.、Moskowitz, N.、Fraser-Reid, B.
DOI:——
日期:——
Liang, David Woei-Ming; Lin, Shu-Fu; Yap, Wen-Yen, Journal of the Chinese Chemical Society, 1994, vol. 41, # 2, p. 175 - 180
作者:Liang, David Woei-Ming、Lin, Shu-Fu、Yap, Wen-Yen、Deng, Yea-Wen