MODIFICATION OF THE NICKL REACTION. A GENERAL SYNTHETIC APPROACH TO 2-VINYL-2,3-DIHYDROBENZOFURANS

Article abstract of DOI:10.1016/S0040-4020(01)97644-6

The annelation reaction of metal phenolates 1 with 1,4-dibromo-2-butenes 2 to give 2-vinyl-2,3-dihydrobenzofuran derivatives 3 (Nickl reaction) was critically examined and markedly improved.Use of lithium phenolates, instead of sodium phenolates, as substrates and toluene, instead of methanol, as reaction medium, caused the yield of annelated compounds to rise dramatically.The relevance of this modified route to the synthesis of Euparinoid 2,3-dihydrobenzofurans and their synthetic analogues was emphasized.