Transition metal catalyzed radical cyclization: new preparative route to .gamma.-lactams from allylic alcohols via the [3.3]-sigmatropic rearrangement of allylic trichloroacetimidates and the subsequent ruthenium-catalyzed cyclization of N-allyltrichloroacetamides
A sequence of reactions including [3.3]-sigmatropic rearrangement of allyl trichloroacetimidates (Overman rearrangement) followed by ruthenium-catalyzed cyclization of N-allyltrichloroacetamides provided a novel method for preparing trichlorinated gamma-lactams from allylic alcohols. No delta-lactam was formed as a byproduct. The cyclization of secondary N-allyltrichloroacetamides proceeded with good diastereoselectivity. Two types of tandem cyclizations to form bicyclic lactams took place in the cyclization of N-allyltrichloroacetamides from geraniol and linalool.
A general method for the synthesis of amines by the rearrangement of allylic trichloroacetimidates. 1,3 Transposition of alcohol and amine functions
作者:Larry E. Overman
DOI:10.1021/ja00426a038
日期:1976.5
Hydrogen bonding control in the oxidative cyclisation of 1,5-dienes
dihydroxylation of a series of functionalised polyenes is described. Under acidic conditions, the osmateester derivatives obtained from oxidation with OsO4/TMEDA undergo an intramolecular cyclisation reaction forming functionalised tetrahydrofurans with high stereoselectivity and in good yield. The generality of this method is illustrated with an application to the synthesis of a bis-tetrahydrofuran ring system