The asymmetric hetero-Diels–Alder reaction of enamide aldehydes with Danishefsky’s diene and an efficient synthesis of chiral binaphthyl ligands
作者:Liu-Zhu Gong、Lin Pu
DOI:10.1016/s0040-4039(00)00193-3
日期:2000.4
By varying the substituents on the nitrogen of enamide aldehydes, their reaction mode with Danishefsky’s diene in the presence of Lewis acid catalysts can be controlled and the desired formal hetero-Diels–Alder products obtained. A new and efficient method to synthesize chiral binaphthyl ligands containing sterically bulky 3,3′-substituents has been developed. Lewis acid complexes prepared from these
Brønsted acids (Chiral LBBAs) have been designed as new organocatalysts for biomimeticenantioselectivecyclization. A salt of a chiral phosphonous acid diester with FSO3H catalyzes the enantioselectivecyclization of 2-geranylphenols to give the desired trans-fused cyclized products with high diastereo- and enantioselectivities (up to 98:2 dr and 93% ee).
Chiral phosphite-urea bifunctional catalysts have been developed for the enantioselective bromocyclization of 2-geranylphenols with N-bromophthalimide (NBP) for the first time.