A kinetically controlled direct aldol addition of alpha-chloro thioesters via soft enolization

作者：Alfie Rachel J; Ngoc Truong; Yost Julianne M; Coltart Don M^*

来源：Tetrahedron Letters, 2017, 58(3): 185-189.

DOI：10.1016/j.tetlet.2016.11.010

• Direct aldol addition
• Soft enolization
• Thioester
• Kinetic control
• alpha-Halo-beta-hydroxy thioester

Herein we report that simple alpha-chloro thioesters undergo soft enolization and direct aldol addition to aldehydes in the presence of MgBr2 center dot OEt2 and i-Pr2NEt. At - 78 degrees C the reaction proceeds in a kinetically controlled manner giving good diastereoselectivity. Significantly, the transformation is applicable to both enolizable and nonenolizable aldehydes. Moreover, excellent stereoselectivity results when a chiral nonracemic alpha-hydroxy aldehyde derivative is used. To our knowledge, this is the first report of a kinetically controlled soft enolization-based aldol addition.

• 出版日期2017-1-18