Hydrogen-Bond Directed Regioselective Pd-Catalyzed Asymmetric Allylic Alkylation: The Construction of Chiral 伪-Amino Acids with Vicinal Tertiary and Quaternary Stereocenters

详细信息    查看全文

• 作者：Xuan Wei ; Delong Liu ; Qianjin An ; Wanbin Zhang
• 刊名：Organic Letters
• 出版年：2015
• 出版时间：December 4, 2015
• 年：2015
• 卷：17
• 期：23
• 页码：5768-5771
• 全文大小：370K
• ISSN：1523-7052

文摘

A Pd-catalyzed asymmetric allylic alkylation of azlactones with 4-arylvinyl-1,3-dioxolan-2-ones was developed, providing 鈥渂ranched鈥?chiral 伪-amino acids with vicinal tertiary and quaternary stereocenters, in high yields and with excellent selectivities. Mechanistic studies revealed that the formation of a hydrogen bond between the Pd-allylic complex and azlactone isomer is responsible for the excellent regioselectivities. This asymmetric alkylation can be carried out on a gram scale without a loss of catalytic efficiency, and the resulting product can be further transformed to a chiral azetidine in two simple steps.