Enantioselective Cyclopropanation with α-Alkyl-α-diazoesters Catalyzed by Chiral Oxazaborolidinium Ion: Total Synthesis of (+)-Hamavellone B

详细信息    查看全文

• 作者：Su Yong Shim ; Jae Yeon Kim ; Miso Nam ; Geum-Sook Hwang ; Do Hyun Ryu
• 刊名：Organic Letters
• 出版年：2016
• 出版时间：January 15, 2016
• 年：2016
• 卷：18
• 期：2
• 页码：160-163
• 全文大小：314K
• ISSN：1523-7052

文摘

Chiral oxazaborolidinium ion-catalyzed asymmetric cyclopropanation of α- or α,β-substituted acroleins with α-alkyl-α-diazoesters has been developed. With this methodology, chiral functionalized cyclopropanes containing a quaternary stereogenic center were obtained with high to excellent enantioselectivities (up to >99% ee). The synthetic utility of optically enriched functionalized cyclopropane was demonstrated in the first total synthesis of (+)-hamavellone B, which establishes the absolute configuration of natural (+)-hamavellone B.