Short, enantioselective total synthesis of aflatoxin B2 using an asymmetric [3+2]-cycloaddition step.
A highly enantioselective [3+2]-cycloaddition reaction of 2,3-dihydrofuran with 1,4-benzoquinones using a chiral oxazaborolidinium triflimidate as catalyst has been developed which allows rapid access to a variety of chiral phenolic tricycles (enantiomeric excesses ranging from 91 to 98%). The utility of this new methodology is demonstrated by a short synthesis of the important pentacyclic natural product, aflatoxin B2. This exploratory study indicates that an even broader application of these catalysts to enantioselective cycloadditions may be possible.
Zhou
Gang
G
Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, USA.
Corey
E J
EJ
D000348:Aflatoxins / Q000138:chemical synthesis*; D016227:Benzoquinones / Q000737:chemistry; D003500:Cyclization; D005663:Furans / Q000737:chemistry; D008956:Models, Chemical; D013237:Stereoisomerism
D000348:Aflatoxins; D016227:Benzoquinones; D005663:Furans; C073812:2,3-dihydrofuran; C029753:aflatoxin B2