Long-range interactions. Part II. A model system for σ-interaction between allylic anion and olefin

Abstract

By successive dechlorination, addition of dichloromethylene, and reduction with lithium in ammonia, isodrin was converted into tetracyclo[5,4,1^2,6,1^8,11,0]trideca-3,9-diene. Two rearrangements resulting from transannular reactions were encountered during the synthesis. Hydrogen isotope exchange experiments were carried out for the tetracyclotridecadiene in perdeuteriodimethyl sulphoxide, and were complicated by a ready thermal rearrangement. Exchange occurred much more slowly than with bicyclo[3,2,1]octa-2,6-diene, where removal of proton by base involves anchimeric assistance from the remote double bond.