Unexpected titanium shifts during cyclopropanation of N,N-dibenzylformamide with ligand-exchanged titanium-alkadiene complexes
作者:Craig M. Williams、Vladimir Chaplinski、Peter R. Schreiner、Armin de Meijere
DOI:10.1016/s0040-4039(98)01665-7
日期:1998.10
A number of readily available dienes and a triene were applied to exchange the alkene ligand on the in situ generated titanium-alkene complexes which react with N,N-dialkylcarboxamides to give N,N-dialkylcyclopropylamines. The ligand-exchanged intermediates were found to give the most highly substituted alkenylcyclopropylamines (abnormal products) in good yields (47-64%), rather than the least substituted alkenylcyclopropylamine (expected products). This has been attributed to an unforeseen and unprecedented titanium migration along the ligand. (C) 1998 Elsevier Science Ltd. All rights reserved.