The stereocontrolled synthesis of tricyclic compounds through an efficient and highly regioselective 5-exo-trig palladium catalyzed biscyclization process is reported, starting from compounds 1. The 6-endo competing cyclization can also be the only pathway leading to trans-octahydrophenanthrene. In this finely balanced competition, it appcared that the 6-endo to 5-exo ratio is dependent upon the size
A study on the regio- and stereoselectivity in palladium-catalyzed cyclizations of alkenes and alkynes bearing bromoaryl and nucleophilic groups
作者:Didier Bruyère、Didier Bouyssi、Geneviève Balme
DOI:10.1016/j.tet.2004.03.023
日期:2004.4
We have studied the remarkable dependence of the stereochemistry of the cyclization on the double bond geometry and of the effect of the bulkiness of the nucleophile on the regiochemistry of the palladium mediated cyclization of alkenes bearing aryl bromides and nucleophiles. In contrast, the cyclization of the acetylenic homologous substrates is not dependent on the nature of the nucleophile.