ALKYNYLIODONIUM SALTS AS ALKYNYLATING REAGENTS - DIRECT CONVERSION OF ALKYNYLPHENYLIODONIUM TOSYLATES TO DIALKYL ALKYNYLPHOSPHONATES WITH TRIALKYL PHOSPHITES

The treatment of various alkynyl(phenyl)iodonium tosylates 1 (R = t-Bu, s-Bu, i-Pr, cyclopentyl, Ph, and p-MeC6H4; X- = OTs-) with neat trimethyl phosphite gave the dimethyl alkynylphosphonates 4a and 4d-h in isolated yields ranging from 34 to 90%. Similar treatment of 1 (R = t-Bu, X- = OTs-) with neat triethyl and triisopropyl phosphites gave the diethyl and diisopropyl alkynylphosphonates 4b (81%) and 4c (58%). The byproducts of these reactions are alkyl tosylates and iodobenzene. The high yields of iodobenzene, determined by GC analysis for the reactions of 1 (R = s-Bu, p-tolyl; X- = OTs-) with trimethyl phosphite, indicate that the cleavage of the alkynyl(phenyl)iodonium ions with trialkyl phosphites proceeds with high regioselectivity at the alkynyl ligand. © 1990, American Chemical Society. All rights reserved.