Pd-Catalyzed Cross-Coupling of Terminal Alkynes with Chromium(0) Fischer Carbene Complexes
作者:Kang Wang、Fengjin Wu、Yan Zhang、Jianbo Wang
DOI:10.1021/acs.orglett.7b01096
日期:2017.6.2
Alkyl chromium(0) carbenecomplexes typically undergo cycloadditions with alkynes to afford carbo- or heterocyclic compounds. In the presence of Pd catalyst, it is demonstrated that a traditional cycloaddition pathway is completely altered: instead of cycloaddition, oxidative cross-coupling reaction of alkyl chromium(0) carbenecomplexes with terminal alkynes occurs. The coupling reaction exhibits
synthesized in moderate to excellent yields from (E/Z)-alkynyl-O-methyl oximes via chlorinative cyclization. The synthesis employs the combination of N-chlorosuccinimide (NCS) and chlorotrimethylsilane (TMSCl) in nitromethane solvent where chlorine (Cl2) and hydrochloric acid (HCl) are generated in situ. In addition, the current protocol is applicable to the synthesis of 4-bromo- and 4-iodoisoxazoles when