Chiral oximes in asymmetric synthesis. Part 2.1 Addition of butyllithium to benzaldehyde O-(1-phenylalkyl)oximes

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Peter T. Gallagher, James C. A. Hunt, Andrew P. Lightfoot and Christopher J. Moody


Abstract

A series of benzaldoxime ethers PhCH[double bond, length as m-dash]NOCHRPh 5 bearing a chiral auxiliary on oxygen have been prepared to investigate the effect of the auxiliary on the diastereoselectivity of the addition of butyllithium to the oxime C[double bond, length as m-dash]N bond. By increasing the size of the alkyl group R in the auxiliary, OCHRPh, an increase in de is observed, with the best compromise between ready availability and high levels of asymmetric induction in the product 6 being achieved with the oximes derived from O-(1-phenylbutyl)hydroxylamine.


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