Total synthesis of natural (+)-FR900482. 2. Efficient syntheses of the aromatic and the optically active aliphatic fragments

Article abstract of DOI:10.1016/0040-4039(96)00594-1

The synthesis of the aromatic fragment 4 was achieved starting from commercially available 5-hydroxy-isophthalic acid (6) by utilizing Claisen rearrangement of 9, bromolactonization of 12, and modified Curtius rearrangement of 16 as key steps. Furthermore, the optically active aliphatic fragment 5 was synthesized in an optically pure form starting with L-diethyl tartrate (7) by featuring epoxide formation of 26, nucleophilic epoxide opening of 27 with an azide anion, reduction of the azide function in 33 to an amine, and formation of the N-protected 1,3-oxazolidine 35.