Exploiting the Lithiation-Directing Ability of Oxetane for the Regioselective Preparation of Functionalized 2-Aryloxetane Scaffolds under Mild Conditions
作者:Donato Ivan Coppi、Antonio Salomone、Filippo Maria Perna、Vito Capriati
DOI:10.1002/anie.201109113
日期:2012.7.23
Oxetane nudges in the DoM direction! Regioselective ortho‐lithiation induced by an oxetane ring has been achieved. The reaction provides easy access to ortho‐functionalized 2‐aryloxetanes also through a lithiation/borylation Suzuki–Miyaura cross‐coupling. The lithiation‐directing ability of oxetane and the proton transfer mechanism have been investigated by competitive metalation and kinetic isotope
The reductive opening of oxetanes by CP2TiCl was investigated by a combined synthetic and computational study. The activation and reaction energies predict a more difficult reaction than the related epoxide opening. Synthetically, the gamma-titanoxy radicals obtained behave like typical free radicals. Their reactions are not controlled by the metal and its ligands. This is highlighted by the dimerization of phenyl substituted oxetane derived radicals. (C) 2008 Elsevier Ltd. All rights reserved.