The first enantioselective decarboxylative aldol addition with α-amido-substituted malonic acid half oxyesters (MAHOs) is described. The combined use of a newly designed bifunctional sulfonamide catalyst with pentafluorobenzoic acid as an additive afforded the β-hydroxy-α-amino acid derivatives in moderate to high yields and with high enantioselectivities.
Investigation of the palladium-catalysed cyclisation of α-amido malonates with propargylic compounds
作者:Sean R. Barlow、Lily J. Callaghan、Vilius Franckevičius
DOI:10.1016/j.tet.2020.131866
日期:2021.1
moderately enantioselective, palladium-catalysed cyclisation with propargylic compounds to afford a broad range of functionalised dihydrooxazine heterocycles. The new dihydrooxazine products will expand the suite of heterocycles available to medicinal chemists, and prompt the investigation of unchartered bis-nucloeophiles in palladium-catalysed cyclisation reactions en route to novel classes of heterocycle
Photochemical alkylation of glycine leading to phenylalanines
作者:Haydn S Knowles、Keith Hunt、Andrew F Parsons
DOI:10.1016/s0040-4039(00)01175-8
日期:2000.9
UV photolysis of protected glycines in the presence of di-tert-butyl peroxide, benzophenone and substituted toluenes is shown to lead to selective alkylation at the α-position. Phenylalanines are isolated in yields of generally >50% (based on recovered starting material).
A photochemical approach to phenylalanines and related compounds by alkylation of glycine
作者:Haydn S Knowles、Keith Hunt、Andrew F Parsons
DOI:10.1016/s0040-4020(01)00783-9
日期:2001.9
Phenylalanines can be prepared on UV photolysis of protected glycines in the presence of di-tert-butylperoxide, substituted toluenes and the photosensitiser benzophenone. These reactions, which lead to highly selective mono-alkylation at the α-position of glycines, involve coupling of captodative α-glycine radicals with benzyl radicals. This method can be used to selectively alkylate a variety of
1,5-Diphenyl-1,2,4-triazole-3-carboxylic acid derivatives for the
申请人:Ciba-Geigy Corporation
公开号:US05077413A1
公开(公告)日:1991-12-31
1,5-Diphenyl-1,2,4-triazole-3-carboxylic acid derivatives of formula ##STR1## wherein each of R.sub.a and R.sub.b, independently of the other, is halogen, C.sub.1 -C.sub.5 alkyl, C.sub.1 -C.sub.5 haloalkyl, C.sub.2 -C.sub.5 alkenyl, C.sub.2 -C.sub.5 alkynyl or cyano, n is zero or a number from 1 to 3 and OR is hydroxy, a phytophysiologically tolerable metal or ammonium salt radical, or an ester radical defined in the description, are capable of specifically antagonizing the phytotoxic action of herbicides. 1,5-Diphenyl-1,2,4-triazole-3-carboxylic acid derivatives of formula I and the preparation thereof, compositions containing these components as selective herbicides and the use of these two active ingredient components for controlling weeds in crops of useful plants are described.