Stereochemical Studies on the Nucleophilic Substitution in the Reaction of Allylic Phosphates with Organoaluminum Reagents

Abstract

Abstract The reaction of cis- or trans-5-isopropenyl-2-methyl-2-cyclohexenyl diethyl phosphate (1) with Me2AlX (X=OPh, SPh, NHPh) in hexane results in substitution of the –O–PO(OEt)2 group with X under predominant inversion. In contrast, treatment of cis- or trans-1 with trialkylaluminum produces predominantly the allyl-nonallyl couplingproducts of the same (thermodynamically more stable) configuration. Similar alkylation of endo- and exo-2-acetoxynorcarane gave endo-2-methylnorcarane, exclusively.