163660-01-3Relevant articles and documents
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Warren et al.
, p. 3422 (1949)
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Enantioselective Synthesis of the Polyketide Antibiotic (3R,4S)-(-)-Citrinin
Roedel, Thomas,Gerlach, Hans
, p. 885 - 888 (2007/10/02)
The fungal metabolite (-)-citrinin (1) was synthesized for the first time.Reaction of the Grignard reagent of 2,4-bis(benzyloxy)-6-bromotoluene (3) with (2S)-trans-(-)-2,3-dimethyloxirane (6) in the presence of 1,5-cyclooctadienecopper(I) chloride as catalyst leads to the formation of (2S,3S)-(-)-7 with erythro configuration.Compound (-)-7 could be transformed into (2R,3S)-(-)-9 with threo configuration via the formate (1R,2S)-(+)-8 by a Mitsunobu reaction.Reaction of the Grignard reagent of 3 with the achiral cis-2,3-dimethyl-oxirane yielded directly (+/-)-9.The starting material 3 was readily available from 1,3-bis(benzyloxy)-5-bromobenzene (4).Formylation of 4 furnished the aldehyde 5 which could be reduced to 3 with borane.Hydrogenolysis of the benzyl ether groups in (-)-9 gave (-)-2 with threo configuration.The remaining steps to produce citrinin from (-)-2 required carboxylation to 11, formylation and in situ ring closure with ethyl orthoformate to produce the required quinomethide structure.Application of the same reactions to (+/-)-9 and (+/-)-2 afforded (+/-)-citrinin in 40percent overall yield. - Key Words: Citrinin, (3R,4S)-(-)- / 2,3-Dimethyloxirane, trans-(-)- and cis- / Synthesis of erythro- and threo-3-arylbutan-2-ols
