Asymmetric synthesis of β- and γ-amidophosphonates by Diels-Alder reaction using chiral aminodiene:: theoretical and experimental study of the facial selectivity of chiral N-dienyl lactam

Asymmetric [4 + 2] cycloaddition of optically pure 1-aminodiene 1 onto substituted phosphonodienophiles 2 and 4 provided respectively chiral beta- and gamma -amidophosphonocyclohexenes with good selectivities. The absolute stereochemistry of the major diastereoisomer was experimentally proved by NMR experiments and the facial selectivity of diene 1 is discussed on the basis of ab initio calculations.