Cyclohepta[b]indole derivatives 7 were prepared by subsequent aza-Claisen rearrangement and intramolecular ring-closure of (cycloheptenylmethyl)benzenamine ( 3 ). The mechanisms of the reactions are also discussed.
Congested C–C Bonds by Pd-Catalyzed Enantioselective Allyl–Allyl Cross-Coupling, a Mechanism-Guided Solution
作者:Michael J. Ardolino、James P. Morken
DOI:10.1021/ja502280w
日期:2014.5.14
Under the influence of a chiral bidentate diphosphine ligand, the Pd-catalyzed asymmetric cross-coupling of allylboron reagents and allylic electrophiles establishes 1,5-dienes with adjacent stereocenters in high regio- and stereoselectivity. A mechanistic study of the coupling utilizing reaction calorimetry and density functional theory analysis suggests that the reaction operates through an inner-sphere 3,3'-reductive elimination pathway, which is both rate-defining and stereodefining. Coupled with optimized reaction conditions, this mechanistic detail is used to expand the scope of allyl allyl couplings to allow the generation of 1,5-dienes with tertiary centers adjacent to quaternary centers as well as a unique set of cyclic structures.
Synthesis of Cycloalkanoindoles, the Carba Analogs of Physostigmine