Stereoselective synthesis of 3-alkyl-2-aryltetrahydrofuran-4-ols: total synthesis of (+/-)-paulownin.

A formal [3 + 2]-cycloaddition involving the Lewis acid mediated reaction of alpha-silyloxy aldehydes and styrenes to afford 3-alkyl-2-aryltetrahydrofuran-4-ols has been developed. This methodology was applied to the total synthesis of the naturally occurring furofuran lignan (+/-)-paulownin.