Divergent Synthesis of Benzo[4,5]imidazo[2,1-b][1,3]thiazines and α-Trifluoromethyl-β-arylthio Tertiary Alcohols from 2-Mercaptobenzimidazoles and α-CF3 Alkenes

• DOI: 10.1021/acs.orglett.4c03765
• Publication Date: 2024-10-25T18:52:39Z
• Authors: Bin Wang; Honghe Lin; Ziren Chen; Yonghong Zhang; Fei Xue; Yu Xia; Shaofeng Wu; Weiwei Jin; Chenjiang Liu

An efficient and metal-free approach for the divergent synthesis of 2-fluoro-3-aryl-4H-benzo[4,5]imidazo[2,1-b][1,3]thiazines and α-trifluoromethyl-β-arylthio tertiary alcohols from 2-mercaptoimidazoles and α-CF3 alkenes has been developed. The chemoselectivity was well controlled by base or light; a series of 2-fluoro-3-aryl-4H-benzo[4,5]imidazo[2,1-b][1,3]thiazines were afforded via base-mediated sequential SN2'- and SNV-type reactions. Meanwhile, α-trifluoromethyl-β-arylthio tertiary alcohols could be selectively achieved through visible-light-driven and electron donor-acceptor (EDA) complex-initiated radical cascade thiolation/hydroxylation in the absence of base, transition metal, and external photocatalyst.