Highly Enantioselective Syntheses of anti Homoaldol Products by (−)-Sparteine-Mediated Lithiation/Transmetalation/Substitution of N-Boc Allylic Amines
摘要:
[GRAPHICS](-)-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.
Highly Enantioselective Syntheses of anti Homoaldol Products by (−)-Sparteine-Mediated Lithiation/Transmetalation/Substitution of N-Boc Allylic Amines
摘要:
[GRAPHICS](-)-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.
Highly Enantioselective Syntheses of <i>anti</i> Homoaldol Products by (−)-Sparteine-Mediated Lithiation/Transmetalation/Substitution of <i>N</i>-Boc Allylic Amines
作者:Marna C. Whisler、Louis Vaillancourt、Peter Beak
DOI:10.1021/ol006186o
日期:2000.8.1
[GRAPHICS](-)-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.