Copper-catalyzed diastereoselective synthesis of β-boryl-α-quaternary carbon carboxylic esters

• DOI: 10.1039/c8ob02469c
• Publication Date: 2018-11-19T13:55:07Z
• Authors: Ya-Jie Zuo; Zhuoran Zhong; Yinkun Fan; Xiangyu Li; Xiaolu Chen; Yuwei Chang; Ruihu Song; Xinpeng Fu; Anling Zhang; Chong-Min Zhong
• Keywords: Quaternary carbon; Carbon fibers

Cu(i)-Catalyzed diastereoselective carboboration of α-alkyl-substituted α,β-unsaturated carboxylic esters to produce β-boryl-α-quaternary carbon was developed. The skeletons dialkyl sulfates, primary allyl halides, and benzyl bromides were transferred the α-position substrates provide products in moderate good yields with a diastereoselectivity >95% most cases. Substrates bearing β-(hetero)aryl substituent gave higher diastereoselectivities than those linear β-alkyl substituent. crystal structure potassium trifluoroborate derivative shows that reactions probably go through copper(i) enolate intermediate arises from electrophilic attack electrophiles less hindered side enolates.