- 3 regioselectively at ambient temperature to give chiral hydroxylamines m 60 - 80% yield. In addition to these products of a formal ene reaction joined by a subsequent hydrolysis 2-substituted hydroxylamines 40 - 49 are also formed. The 2-substituted hydroxylamines 40, 41, 49 possess trans configurations exclusively. The product distribution is solvent dependent and susceptible to the addition of
Silver Salt-Mediated Allylation Reactions Using Allyl Bromides
作者:Xiaodong Xiong、Jonathan Wong、Ying-Yeung Yeung
DOI:10.1021/acs.joc.1c00480
日期:2021.5.7
A facile, efficient, and chemoselective synthesis of allylic amides has been developed. Allyl bromides were used as the precursors activated by silver triflate. A Ritter-type reaction readily proceeded to give various allyl amides under mild conditions. The reaction protocol was also applicable to different nucleophilic partners to give a wide range of allyl-substituted products in the absence of a
Palladium-catalysed asymmetric allylic substitution: synthesis of α- and β-amino acids
作者:Justin F. Bower、Roshan Jumnah、Andrew C. Williams、Jonathan M. J. Williams
DOI:10.1039/a606586d
日期:——
Methodology has been established for the formation of
enantiomerically enriched α-amino acids using palladium-catalysed
allylic amination. The formation of enantiomerically enriched
allylamines has been achieved with high enantioselectivity. Oxidative
cleavage of the allylamines provides arylglycine and glutamic acid
derivatives. Additionally, enantiomerically enriched β-amino acids
have been prepared in high enantiomeric excess. Palladium-catalysed
asymmetric allylic substitution is used as the key synthetic
transformation.
Synthesis of N-protected amino esters via palladium catalysed allylic substitution
作者:Roshan Jumnah、Jonathan M.J. Williams、Andrew C. Williams
DOI:10.1016/0040-4039(93)88120-8
日期:1993.10
N-protected allylamines were prepared by palladium catalysed allylic substitution of the corresponding allyl acetates with a range of nitrogen nucleophiles. The so-formed N-protected allylamines were subjected to oxidative cleavage of the alkene to afford N-protectedaminoacids or esters.
Switching and Conformational Fixation of Amides Through Proximate Positive Charges
作者:Amelie L. Bartuschat、Karina Wicht、Markus R. Heinrich
DOI:10.1002/anie.201502474
日期:2015.8.24
Tertiary amides, which usually occur as cis/trans mixtures, can be effectively shifted to the cis conformation by placing a positive charge in close proximity to the amide carbonyl. This effect was used to prepare cis‐configured prolyl amides and to facilitate a strongly rotamer‐dependent radical cyclization.