Initial Interaction of Triphenylphosphonium-2-propenylide with Prenal Prior to Wittig Olefination
摘要:
The interaction of triphenylphosphonium-2-propenylide (2) with prenal (6) is shown to proceed via initial C-gamma-C-1 addition, followed by dissociation of the coupling product and C-alpha-C-1 recombination to produce the corresponding betaine, which eliminates triphenyphosphine oxide to yield (E)- and (Z)-6-methyl-1,3,5-triene (7a,b) as the Wittig olefination products.
van Dongen,J.P.C.M. et al., Recueil des Travaux Chimiques des Pays-Bas, 1967, vol. 86, p. 1077 - 1081
作者:van Dongen,J.P.C.M. et al.
DOI:——
日期:——
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.