Enantioenriched synthesis of cyclopropenes with a quaternary stereocenter, versatile building blocks
Misaki Uehara1, Hidehiro Suematsu, Yoichi Yasutomi
1Department of Chemistry, Faculty of Science, Graduate School, and Institute for Advanced Study, Kyushu University, Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan.
Abstract:
Ir(salen) complexes were found to catalyze enantioselective cyclopropenation efficiently. Cyclopropenation can be carried out using either a donor/acceptor- or an acceptor/acceptor-substituted diazo compound such as α-aryl-α-diazoacetates, α-phenyl-α-diazophosphonate, 2,2,2-trifluoro-1-phenyl-1-diazoethane, and α-cyano-α-diazoacetamide as carbenoid precursors. The reactions provide highly enantioenriched cyclopropenes (84-98% ee) with a functionalized quaternary carbon as versatile building blocks.
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