The mechanism of the reaction between nitrones and lithium ynolates has been studied using DFT methods at the M06-2X/cc-pVTZ/PCM=THF level. After the formation of a starting complex an without energy barrier, in which the lithium atom is coordinated to both nitrone and ynolate, the reaction takes place in one single kinetic step through a single transition structure. However, the formation of C...

The synthesis of enantiopure N-benzylidene nitrones of N-hydroxy-alpha-amino acids and their incorporation using standard Fmoc-based peptide chemistry into solid-supported peptide chains is described. Deprotection and resin cleavage affords N-terminal peptide hydroxylamines, which are the key substrates for chemoselective ligations with C-terminal peptide alpha-ketoacids. This general route is ...

Stereoselective vinylogous Mannich reaction of 2-trimethylsilyloxyfuran with L-gulose-derived chiral nitrones in the presence of a catalytic amount of trimethylsilyl trifluoromethanesulfonate was investigated. The selectivity was strongly influenced by the bulkiness of the C-substituent of the nitrone: for example, C-benzyloxymethyl nitrone afforded four stereoisomers, whereas bulky C-[(4S)-2,2...

Highly useful optically active 1-(1-alkynyl)cyclopropyl ketones can be efficiently obtained by the kinetic resolution of the easily available racemic ones under the catalysis of the chiral gold(I) species. Reaction scope and synthetic applications are also investigated.

The title compound, C(19)H(16)N(4)O(2)·0.425CH(4)O, crystallizes with two formula units per asymmetric unit. Researching its crystal structure constitutes part of a study of the nature of inter-actions between the N(+)-O(-) group and the vicinal NH group. The nitrone group and methanol solvent mol-ecules are linked via four N-H⋯O and one O-H⋯O hydrogen bonds, with donor-acceptor distances of 2....

N-Oxidation of 1,4-dihydro-2,6-dimethyl-1- phenyliminopyridine (7) with several peracids was attempted. The main compound obtained was l-phenyl- 2,6-dimethyl-4-pyridone (8), instead of the expected N-oxide (2). The reaction of phenylhydroxylamine with dimthylrnethoxypyroxonium perchlorate, however, successfully gave the N-oxide (3), which belongs to a class of nitrones in which the diazomet...

A general procedure for the nucleophilic addition of organozinc halides with nitrones in the presence of trimethylsilyl chloride has been developed. Trimethylsilyl chloride was found to be both an indispensable reaction promoter and a ready hydroxylamine protective agent in these reactions. The produced O-(trimethylsilyl)hydroxylamines can be easily reduced into corresponding amines just by a z...