A new class of substrates for nucleophilic 5-endo-trig cyclization, 2-trifluoromethyl-1-alkenes: synthesis of five-membered hetero- and carbocycles that bear fluorinated one-carbon units.
Disfavored 5-endo-trig cyclizations were achieved in 2-trifluoromethyl-1-alkenes with a nucleophilic nitrogen, oxygen, sulfur, or carbon atom through 1) intramolecular S(N)2' reaction with loss of a fluoride ion or 2) intramolecular nucleophilic addition to the vinylic group. This reaction manifold provides a versatile method for the synthesis of indolines, indoles, pyrrolidines, tetrahydrofurans, 2,3-dihydrobenzo[b]thiophenes, tetrahydrothiophenes, and cyclopentanes that bear a fluorinated one-carbon unit such as a difluoromethylene, difluoromethyl, or trifluoromethyl group.
Ichikawa
Junji
J
Department of Chemistry, Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8571, Japan. junji@chem.tsukuba.ac.jp
Iwai
Yu
Y
Nadano
Ryo
R
Mori
Takashi
T
Ikeda
Masahiro
M