A General Method for the Vinylation of Nitrones. Synthesis of Allyl Hydroxylamines and Allyl Amines
摘要:
An examination of the vinylation of several nitrones is presented. Whereas a complete diastereofacial discrimination was observed upon the addition of vinyl organometallic reagents to alpha-alkoxy nitrones, the same reaction with alpha-amino nitrones pave syn adducts in all cases, with the only exception of a L-serine-derived alpha-amino monoprotected nitrone. The obtained allyl hydroxylamines were easily transformed into synthetically valuable allyl amines.
Highly diastereoselective nucleophilic addition of organometallic reagents to 2-pyrrolidinyl nitrones: a semiempirical approach
作者:Pedro Merino、Santiago Franco、Jose M. Gascon、Francisco L. Merchan、Tomas Tejero
DOI:10.1016/s0957-4166(99)00203-7
日期:1999.5
2-Pyrrolidinyl nitrones 1 and 2 derived from l-proline and trans-4-hydroxy-l-proline, respectively, undergo nucleophilic additions of Grignard reagents and organolithium compounds with high syn selectivity, to yield enantiomerically pure pyrrolidinyl benzyl hydroxylamines. A rationale for the observed stereoselectivity based on semiempirical calculations is presented.
O -Silyl triflate-promoted addition of diethyl phosphite to chiral aldonitrones. A rapid access to complex α-amino phosphonates and their N -hydroxy derivatives
作者:Carmela De Risi、Alessandro Dondoni、Daniela Perrone、Gian Piero Pollini
DOI:10.1016/s0040-4039(01)00363-x
日期:2001.4
The addition reaction of diethyl phosphite to O-silylated N-benzyl nitrones derived from chiral alpha -alkoxy and N-Boc alpha -amino aldehydes has been studied as a stereoselective carbon-phosphorus bond forming process for the synthesis of polyhydroxylated alpha -amino and alpha,beta -diamino phosphonates. Key intermediates are the corresponding N-hydroxy alpha -amino phosphonates. (C) 2001 Elsevier Science Ltd. All rights reserved.