Silver(I)-Catalyzed Aminocyclization of 2,3-Butadienyl and 3,4-Pentadienyl Carbamates: An Efficient and Stereoselective Synthesis of 4-Vinyl-2-oxazolidinones and 4-Vinyltetrahydro-2<i>H</i>-1,3-oxazin-2-ones
作者:Masanari Kimura、Shuji Tanaka、Yoshinao Tamaru
DOI:10.1246/bcsj.68.1689
日期:1995.6
Silver(I) salts in combination with an appropriate base (mostly triethylamine) catalyzed the aminocyclization of N-substituted 2,3-butadienyl carbamates 1 (benzene, 50 °C) to provide 4-vinyl-2-oxazolidinones 2 in good yields. The stereoselectivity (trans-2/cis-2) ranged from 1.4 for C5-Me to >30 for C5-phenyl, isopropenyl, and t-butyl derivatives. 3,4-Pentadienyl tosylcarbamates 3, the one-carbon higher homologues of 1, underwent a similar cyclization to give 4-vinyltetrahydro-2H-1,3-oxazin-2-one 4 in synthetically useful yields and in higher trans selectivities than 1.
A direct method for the preparation of trifluoroacetimides has been extended to the preparation of trifluoroacetyl trifluoracetimide and the new compound trifluoromethylsulfuryl trifluoroacetimide. Points concerning previously reported syntheses of trifluoroacetyl isocyanate have also been clarified.
carbodiimides RN=C=NSO2CF3 are formed in high yield. In other words, an aza Curtiusrearrangement occurs. The carbodiimides react with water, alcohols, and secondary amines to give corresponding ureas, isoureas, and guanidine derivatives. Imidoyl chlorides with substituents other than SO2RF do not enter into the aza Curtius reaction.
The present invention provides compounds represented by the formula Y
+−
N(SO
2
R
f
)(CF
3
). Such a compound can be manufactured through a reaction between M
+−
N(SO
2
R
f
)(CF
3
) and Y
+−
B. The present invention also provides compounds represented by the formula Y
+−
N(SO
2
R
f
)(CN). Such a compound can be manufactured through a reaction between M
+−
N(SO
2
R
f
)(CN) and Y
+−
B. R
f
in the above formulae is a perfluoroalkyl group. Y
+
is an organic or inorganic cation.
−
B is an organic or inorganic anion. M
+
is an alkali metal cation or a silver cation.
(Perhalogenmethylthio)heterocyclen XXV [1] : Synthese von N-substituierten 2,3,4,5-Tetrakis(trifluormethylthio)pyrrolen
作者:Alois Haas、Christiane Klare
DOI:10.1016/s0022-1139(00)82755-4
日期:1989.2
1-Chloro-2,3,4,5-tetrakis(trifluoromethylthio)pyrrole (1b) is a good starting material for the preparation of other N-substituted derivatives of this type. Treatment with NaNH2 or hydrazine provides facile routes to the corresponding amino- (1c) and hydrazino- (2a) compounds. The latter forms with CF3SO2NCO the expected urea derivative (2c). Hydrolysis of 1c leads to 1-hydroxytetrakis(trifluoromethylthio)pyrrole
1-氯-2,3,4,5-四(三氟甲硫基)吡咯(1b)是制备此类其他N-取代衍生物的良好起始原料。用NaNH 2或肼处理提供了通往相应氨基(1c)和肼基(2a)化合物的简便途径。后者与CF 3 SO 2 NCO形成预期的尿素衍生物(2c)。1c水解会生成1-羟基四(三氟甲硫基)吡咯(2d)。将HC(O)H插入四(三氟甲硫基)吡咯(1a)的NH键中,制得与CF 3 SO 2 NCO,C 6 H 5 NCO,2-Cl-C 6 H形成的类似取代的甲醇(2b)4 SO2 NCO和C 6 H 5 CONCS期望的导数2c-h。用(CH 3)3 SiCl和2b形成甲硅烷基醚2i。