Total asymmetric synthesis of the potent immunosuppressive marine natural product microcolin A

The total asymmetric synthesis of the potent immunosuppressive compound microcolin A is reported, The synthesis establishes the absolute stereochemistry of microcolin A as C-36R, C-38R, and C-4S on the basis of the diastereoselective preparation of all four possible diastereomers of the lipid region (fragment A) and diastereoselective synthesis of fragment C starting from natural L-(S)-alanine. The strategy involves a convergent assemblage of three optically pure fragments and is amenable to chemical modifications to examine structural analogs for biological study.