A practical semi-synthesis of tautomycin using a hydrolysate of natural tautomycin
摘要:
A useful and brief semi-synthesis of tautomycin, which can be supplied a large quantity, has been achieved through the coupling reaction of the C21-C26 segment (an epoxide) with the C1-C20 segment (a dithiane), which was derived from the degradation of natural tautomycin, toward the conformational analysis of the C21-C26 moiety and the exploration of structure-activity relationships. (C) 2003 Elsevier Ltd. All rights reserved.
The 2,3-disubstituted maleic anhydride segment of tautomycin has been synthesized in optically active form. Oxidation of 3,4-disubsrituted furan employing singlet oxygen completes the construction of the maleic anhydride moiety. Esterification of the maleic anhydride segment without protecting anhydride moiety resulted in the successful coupling reaction with fragment derived from tautomycin.
One of the three spiro-segments in the synthesis of okadaic acid was synthesized under a new heteroconjugate addition strategy. Successive coupling of this spiro-segment with two tautomycin-synthetic segments afforded a hybrid molecule between okadaic acid and tautomycin.
The synthesis of Segment B/C corresponding to the C26 through to the C1 positions of tautomycin was achieved by coupling between Segment B (an epoxide) and Segment C (a sulfone carbanion) in the presence of boron trifluoride etherate (BF3·OEt2). Two routes have been developed in esterification of Segment A with Segment B/C. The first route employed Segment A with furan moiety as masked maleic anhydride