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Enantioselective organocatalysis using SOMO activation.

Science (New York, N.Y.) (2007-03-31)
Teresa D Beeson, Anthony Mastracchio, Jun-Bae Hong, Kate Ashton, David W C Macmillan
ABSTRACT

The asymmetric alpha-addition of relatively nonpolar hydrocarbon substrates, such as allyl and aryl groups, to aldehydes and ketones remains a largely unsolved problem in organic synthesis, despite the wide potential utility of direct routes to such products. We reasoned that well-established chiral amine catalysis, which activates aldehydes toward electrophile addition by enamine formation, could be expanded to this important reaction class by applying a single-electron oxidant to create a transient radical species from the enamine. We demonstrated the concept of singly occupied molecular orbital (SOMO) activation with a highly selective alpha-allylation of aldehydes, and we here present preliminary results for enantioselective heteroarylations and cyclization/halogenation cascades.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
(2S,5S)-(−)-2-tert-Butyl-3-methyl-5-benzyl-4-imidazolidinone, 97%