Highly efficient synthesis of allylic alcohols having an α-alkoxyalkyl group at their β-position via regioselective addition reaction of titanium-propargyl ether complexes with carbonyl compounds

Abstract

Diisopropoxytitanium-propargyl ether complexes 2, readily generated in situ from Ti(OPr i) 4 2 i PrMgBr reagent and propargylic ethers 3, react with aldehydes and ketones highly regioselectively at the carbon having an α-alkoxyalkyl group, thus affording an efficient and practical method for synthesizing allylic alcohols 4 having an α-alkoxyalkyl group at the β-position. The synthesis of conjugated dienes 7h and 8h from the resulting 4h is also described.