A New Family of Conformationally Constrained Bicyclic Diarylprolinol Silyl Ethers as Organocatalysts

Simple chemical manipulations of trans-4-L-hydroxy proline allow the access to a new family of bicyclic silyl ether organocatalysts that display some remarkable features. Apart from being extremely stable to hydrolytic conditions and possessing excellent catalytic performances, the rigidity of the bicyclic structure imposes a synclinal endo disposition of the bulky substituents with respect to the pyrrolidine ring, opposed to the more stable synclinal exo conformations of JorgensenHayashi catalysts.