Phosphine-Catalyzed Divergent [4+3] Domino Annulations of CF<sub>3</sub>-Containing Imines with MBH Carbonates: Construction of Perfluoroalkylated Benzazepines
作者:Junlong Chen、Zhongmo Yin、You Huang
DOI:10.1021/acs.orglett.9b02626
日期:2019.9.6
Phosphine-catalyzed divergent [4+3] domino annulations of fluorinated imidoylchlorides with MBH carbonates were developed. Two classes of perfluoroalkylated benzazepines were obtained in moderate to good yields via an interesting dearomatization/rearomatization sequence. Remarkably, the fluorinated imidoylchlorides could be utilized for the first time as a new four-atom building block in phosphine catalysis. Moreover
2-Iminothiazolidin-4-one, 5-ethylidenethiazolidin-4-one, and thiazolidine-4-thione are all medicinally relevant structures. In this work, a NaSO2CF3-promoted [2+2+1] cascade annulation reaction of CF3-imidoyl sulfoxonium ylides and isothiocyanates was reported to synthesize a variety of decorated thiazolidine-4-thiones in 35–91% yields with exclusive stereoselectivity. The gram-scale reaction and further
CF3-imidoyl sulfoxonium ylides and terminalalkynes has been demonstrated. This work provides a practical approach for assembling 5-trifluoromethylpyrroles with the merits of a broad substrate scope, good functional tolerance, and mild reaction conditions. Control experiments and DFT studies indicate that this reaction may involve the addition of π-bonds of terminalalkynes by copper-carbene radicals