Tandem addition/cyclization reaction of organozinc reagents to 2-alkynyl aldehydes: Highly efficient regio- and enantioselective synthesis of 1,3-dihydroisobenzofurans and tetrasubstituted furans

The enantioselective addition of organozinc reagents to some 2-alkynyl benzaldehydes and the subsequent regioselective cyclization step was performed in one pot to form chiral 1,3-dihydroisobenzofurans with good product yields and excellent regio- and enantioselectivities. In the case of 2-alkynyl-cycloalkene aldehydes, tetrasubstituted furans were obtained in good product yields through a 1, 5-hydride shift of the preformed cyclization product.