Synthesis of 4-oxepanones by the Lewis acid-promoted ring-expansion reaction of cyclopropapyranones
摘要:
In the presence of a Lewis acid, cyclopropapyranones easily reacted with silyl enolates to give the 4-oxepanones in good yields. In this reaction, the trans-isomer was mainly obtained. (C) 2001 Elsevier Science Ltd. All rights reserved.
versatile chiral building block. The strategy is based on three key transformations: enantioselective hetero-Diels−Alder (HDA) reaction of aldehyde with Danishefsky’s diene, selective reduction of carbonyl function, and Claisen or related rearrangement. The synthetic utility of the methodology is illustrated by totalsynthesis of antibiotic (−)-centolobine.
presence of lithiumdialkylamides to functionalized 2,3-dihydropyrans or 2,3-dihydrofurans, respectively, is described. The regiochemical outcome of the reaction can be influenced by the relative configuration of the starting epoxides and the steric demand of the base. The 2,3-dihydropyrans obtained were converted stereoselectively to difunctionalized 3,4-dihydropyrans by the carbon-Ferrier reaction, or to
A new approach to the stereoselective synthesis of C-glycosides from glycals with various organoaluminum reagents has been demonstrated.
利用各种有机铝试剂立体选择性合成 C-糖苷的新方法已经得到证实。
Synthesis of (±)-Diospongin A: A Hetero-Diels-Alder and C-Glycosylation Approach
作者:Jesse More
DOI:10.1055/s-0029-1218784
日期:2010.7
The racemic natural product diospongin A has been prepared using a short and stereoselective sequence. Key steps include a hetero-Diels-Alder reaction and an anchimeric assistance-controlled C-glycosylation
外消旋天然产物薯海绵素 A 是使用短的立体选择性序列制备的。关键步骤包括异狄尔斯-阿尔德反应和嵌合辅助控制的 C-糖基化
Berkowitz, David B.; Danishefsky, Samuel J.; Schulte, Gayle K., Journal of the American Chemical Society, 1992, vol. 114, # 12, p. 4518 - 4529
作者:Berkowitz, David B.、Danishefsky, Samuel J.、Schulte, Gayle K.