Selective Formation of 1 out of 64 Stereoisomers

Significance

Jørgensen and co-workers have developed an organocatalytic asymmetric one-pot cascade reaction for the synthesis of optically active bicyclo[3.3.1]non-2-enes 4 starting from two simple molecules, an enal 1 and a tricarbonyl compound 2. α,α-Diphenylprolinol trimethylsilyl ether (3) together with benzoic acid was used as chiral catalyst. The process features the selective formation of four new carbon-carbon bonds and six new stereocenters, thereby providing one out of 64 (2⁶) possible stereoisomers with excellent ­diastereo- and enantioselectivity.