2 siloxyfuran vinylogous Mannich reaction

Under similar conditions, the same authors were able to control two stereogenic centers in an asymmetric vinylogous Mannich reaction. Indeed, treatment of imines derived from aryl a-ketoesters with siloxyfuran under related conditions gave functionalized y-butenolides with high diastereo- and enantioselectivities (Scheme 10.21 ).40... 

The enantioselective vinylogous Mannich reaction of siloxyfurans with ketimines catalyzed by a cinchona alkaloid amide/Cu(OAc)2 combination afforded furan-2(5fJ)-one containing contiguous tetra- and trisubstituted stereocenters with high selectivity (13AGE5557). 

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