299908-69-3Relevant academic research and scientific papers
Synthetic applications of lithiated N-Boc allylic amines as asymmetric homoenolate equivalents
Whisler, Marna C.,Beak, Peter
, p. 1207 - 1215 (2007/10/03)
Lithiation of N-(Boc)-N-(p-methoxyphenyl) allylic amines in the presence of (-)-sparteine provides asymmetric homoenolate equivalents which react with electrophiles to provide highly enantioenriched enecarbamates. Acidic hydrolysis of the enecarbamates can provide the corresponding β-substituted aldehydes. A synthetic sequence that involves a stereocontrolled intramolecular nitrone-olefin dipolar cycloaddition has been developed for the preparation of enantioenriched 2-formyl-4-phenyl-1-aminocyclopentanes from one β-allyl-substituted aldehyde. Further manipulations allow access to an enantioenriched β-lactam. In another synthetic sequence, transmetalation of the lithiated intermediates and reactions with aldehyde electrophiles can be controlled to afford highly enantioenriched anti homoaldol products. Use of an anti aldehyde homoaldol product as the chiral electrophile in an iterative reaction provides a double homoaldol product containing four stereogenic centers with high diastereoselectivity and enantioselectivity. Reaction pathways are proposed to account for the observed products.
Highly enantioselective syntheses of anti homoaldol products by (-)-sparteine-mediated lithiation/transmetalation/substitution of N-Boc allylic amines
Whisler, Marna C.,Vaillancourt, Louis,Beak, Peter
, p. 2655 - 2658 (2007/10/03)
(equation presented) (-)-Sparteine-mediated lithiation/transmetalation/substitution of N-Boc allylic amines provides anfi-configured homoaldol precursors in yields of 38-85% and enantiomeric ratios of 83:17-99:1. Subsequent O-protection and hydrolysis all
