Highly Enantioselective Syntheses of anti Homoaldol Products by (−)-Sparteine-Mediated Lithiation/Transmetalation/Substitution of N-Boc Allylic Amines
- 28 July 2000
- journal article
- research article
- Published by American Chemical Society (ACS) in Organic Letters
- Vol. 2 (17), 2655-2658
- https://doi.org/10.1021/ol006186o
Abstract
(−)-Sparteine-mediated lithiation/transmetalation/substitution of N-Boc allylic amines provides anti-configured homoaldol precursors in yields of 38−85% and enantiomeric ratios of 83:17−99:1. Subsequent O-protection and hydrolysis allows access to O-protected homoaldol adducts in good yields. The absolute configurations of the homoaldol products have been assigned by calculation of optical rotations and by X-ray crystallography of derivatives. A stereochemical course of reaction for the lithiation/transmetalation/substitution sequence is proposed.Keywords
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