Ti-mediated intramolecular cyclopropanation of N-alkenyl thioamides: scope and mechanistic study
摘要:
Although thioamides generally undergo a reductive alkylation process when they are treated with a Grignard reagent in the presence of Ti(OiPr)(4), substrates fitted with a but-3-enyl substitution at the nitrogen atom are shown to be converted into bicyclic aminocyclopropanes. These reactions are compared with the similar cyclisations of the corresponding carboxylic amide substrates. A mechanistic study is provided. Coincidently, new reagent systems are identified for the mediation of the same transformation. (C) 2014 Elsevier Ltd. All rights reserved.
Intramolecular Kulinkovich–de Meijere reactions of various disubstituted alkenes bearing amide groups
摘要:
A range of amides fitted with (E) or (Z) disubstituted alkene groups were prepared and evaluated in intramolecular Kulinkovich-de Meijere reactions. The corresponding aminocyclopropanes were obtained with high diastereoselectivity. Good yields could be achieved with substrates bearing suitable substitutions at the olefin moieties. (C) 2008 Elsevier Ltd. All rights reserved.