Reaction mechanisms
Part (ii) Pericyclic reactions
Abstract
This report surveys the 2005 literature on mechanisms of pericyclic reactions. Of particular note are reports on boron-induced torquoselectivity in 4-electron electrocyclic ring-openings, a transition structure for a 10-electron electrocyclization that sports a double-twist Möbius orbital array, several studies that further demonstrate the relevance of stepwise diradical mechanisms for [1,3] sigmatropic shifts, characterization of a “stable transition state” for a [3,3] sigmatropic shift, and both experimental and theoretical evidence for several new pericyclic reactions in biological systems.