摘要:
                                An asymmetric synthesis of tetrahydrolipstatin (4) is described.  Application of our previously described in situ cyclopentadiene alkylation-asymmetric hydroboration protocol provided the key chiral alcohol 9.  In the course of this work, the presence of a free hydroxyl group was found to exert a strong directing effect on the regioselectivity of a Baeyer-Villiger reaction (16 --> 17).  Subsequent transformations of lactone 17 produced tetrahydrolipstatin (4).