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Enantioselective Protonation of the Lithium Transient Enolate of2‐Methyltetralone with 2‐Sulfinyl Alcohols
Author(s) -
Gil Jesús,
MedioSimon Mercedes,
Mancha Gisela,
Asensio Gregorio
Publication year - 2005
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.200400812
Subject(s) - chemistry , enantioselective synthesis , protonation , ketone , enol , stereoselectivity , cyclohexanol , alcohol , alkoxide , medicinal chemistry , lithium (medication) , organic chemistry , catalysis , stereochemistry , ion , medicine , endocrinology
A new catalytic cycle for the enantioselective protonation of cyclic ketone enolates with sulfinyl alcohols has been developed. An enol trifluoroacetate that can be easily obtained from the corresponding ketone is used for the first time as an enolate precursor of a cyclic ketone enolate. In this method, the achiral alcohol plays two roles: it is involved, as is usual in catalytic asymmetric protonation reactions, in the turnover of the chiral proton source and also in the generation of a transient enolate through the reaction of its corresponding alkoxide with the enol trifluoroacetate precursor. Stereoselectivity is highly dependent on the structure of the achiral alcohol. High levels of stereoselectivity can be achieved with the use of cyclohexanol. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)