A Mismatch-Free Strategy for the Diastereoselective α,α-Bisalkylation of Chiral Nonracemic Methyl Ketones
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Published on: May 16, 2012
Md Nasir Uddin1, Emily M Tarsis1, Chia-Hua Wu1
1Department of Chemistry , University of Houston , Houston , Texas 77204-5003 , United States.
Abstract:
A chiral auxiliary-based diastereoselective transformation that entirely avoids the stereochemically mismatched pairing, providing equally high levels of asymmetric induction in the formation of each diastereomer is described. In particular, we show that chiral nonracemic methyl ketones undergo α,α-bisalkylation using phenylalanine-derived N-amino cyclic carbamate (ACC) auxiliaries with essentially perfect diastereoselectivity, as well as excellent yield and regioselectivity. Significantly, with the use of a single enantiomer of the auxiliary, either diastereomeric product can be synthesized with an equally high level of asymmetric induction.
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