Diastereoselective synthesis of tetrahydrofurans via palladium(0)-catalyzed [3+2] cycloaddition of vinylcyclopropaines and aldehydes

Palladium(0)-catalyzed cycloadditions of malonate-derived vinylcyclopropane 1 and aldehydes to afford 2,5-ci disubstituted tetrahydrofuran derivatives are described. Pd loadings as low as 0.5 mol % were effective in catalyzing the transformation with high yields and diastereoselectivities. Electron-poor aldehydes work best, suggesting that a mechanism involving an initial aldol reaction may be operative.