Synthesis of a C4-epi-C1-C6 fragment of FR901464 using a novel bromolactolization.

[reaction: see text] A synthesis of a C4-epi-C1-C6 fragment of the antitumor agent FR901464 is reported. The advanced intermediate prepared in this study contains two of the three correct stereocenters found in the C1-C6 moiety of FR901464. For the preparation of this intermediate, we have developed a highly diastereoselective bromolactolization of a delta-alkenyl ketone.