Brønsted Base-Modulated Regioselective Pd-Catalyzed Intramolecular Aerobic Oxidative Amination of Alkenes: Formation of Seven-Membered Amides and Evidence for Allylic C−H Activation
作者:Liang Wu、Shuifa Qiu、Guosheng Liu
DOI:10.1021/ol900941t
日期:2009.6.18
A novelpalladium-catalyzed intramolecular aerobic oxidative allylic C−H amination of olefins has been developed. Brønsted base can modulate the regioselectivity, favoring the formation of 7-membered rings. Mechanistic studies using deuterium-labeled substrates as probes support a rate-determining allylic C−H activation/irreversible reductive elimination pathway.
Diastereoselective synthesis of substituted dihydropyrans via an oxonium–ene cyclization reaction
作者:Pipas Saha、Priya Ghosh、Sabera Sultana、Anil K. Saikia
DOI:10.1039/c2ob26088c
日期:——
Substituteddihydropyrans can be efficiently synthesized in good yields with excellent diastereoselectivity from the reaction of aldehydes or epoxides and ethyl 3-alkyl-3-hydroxy-5-methylhex-5-enoate via an oxonium–ene cyclization reaction catalyzed by trimethylsilyl trifluoromethanesulfonate (TMSOTf) under mild conditions.