Decarboxylative radical addition to vinylsulphones and vinylphosphonium bromide: Some further novel transformations of geminal (pyridine-2-thiyl) phenylsulphones.
摘要:
Irradiation of O-acyl derivatives 1 of N-hydroxy- 2-thiopyridone with visible light in the presence of phenyl vinyl sulphone or vinyl triphenylphosphonium bromide leads to the corresponding adducts 8 and 9 which can undergo a wide variety of further transformations.
作者:Derek H.R. Barton、Dominique Bridon、Samir Z. Zardb
DOI:10.1016/s0040-4020(01)87707-3
日期:1987.1
Irradiation of esters 3 derived from aliphatic or alicyclic carboxylic acids and N-hydroxy-2-thiopyridone in the presence of various quinones gives high yields of the corresponding adducts (e.g. 9) with net loss of carbon dioxide.
作者:Derek H.R. Barton、Dominique Bridon、Isabel Fernandaz-Picot、Samir Z. Zard
DOI:10.1016/s0040-4020(01)86878-2
日期:1987.1
Esters (mixed anhydrides) derived from aliphatic or alicyclic carboxylic acids (RCO2H) and thiohydroxamic acids or undergo a thermally or photochemically induced radical chain reaction to give sulphides with loss of carbon dioxide. On irradiation at low-temperature however, the chain reaction is essentially supressed. Under these conditions moderate to good yields of dimers R-R are obtained from primary
The invention of new radical chain reactions. part X
作者:Derek H.R. Barton、Hideo Togo、Samir Z. Zard
DOI:10.1016/s0040-4020(01)91351-1
日期:1985.1
oxidised to carboxylic acids by treatment with alkaline hydrogen peroxide. Reductive cleavage to the corresponding aldehydes or ketones is efficiently carried out by the action of TiCl3. Addition of methylmagnesiumiodide to the methyl ketone derived from 3α-acetoxy 11-oxo cholanic acid gives steroid possessing the 25-hydroxycholesterol side chain of the vitamin D3 metabotites. Radical additions to
衍生自硫代异羟肟酸酯的自由基容易加到硝基烯烃(Z = NO 2)中,从而获得高产率的α-亚硝基硫化物。在结构允许的情况下,这些加合物通过用碱性过氧化氢处理很容易被氧化成羧酸。通过TiCl 3的作用,可以有效地进行相应的醛或酮的还原裂解。将甲基碘化镁加到衍生自3α-乙酰氧基11-氧代胆酸的甲基酮中,得到的类固醇具有维生素D 3代谢物的25-羟基胆固醇侧链。简述了对1-苯基硫-2-硝基丙烯的自由基加成反应。
Concise syntheses of L-selenomethionine and of L-selenocystine using radical chain reactions
作者:Derek H.R. Barton、Dominique Bridon、Yolande Hervé、Pierre Potier、Josiane Thierry、Samir Z. Zard
DOI:10.1016/s0040-4020(01)88049-2
日期:1986.1
from (e.g. ) in the presence of dimethyldiselenide provided the protected L-selenomethionine directly. We have shown that triselenocyanide Se3(CN)2 can serve as an efficient selenocyanating agent for radicals; the selenocyanide group is a good precursor for the diselenide moiety of L-selenocystine.
probably proceeds via Dexter energy transfer between the activated catalyst and the Barton ester. Furthermore, a one-pot wavelength-selective reaction within the visible light range is developed in combination with a blue-light-mediated photoredox reaction, demonstrating the compatibility of two photochemical transformations based on mechanistic differences. This one-pot process expands the limits of the