开发了一种碱促进的有机铵盐直接脱氨基烯化。仅由 KO t Bu 介导,一系列苄基和肉桂基铵盐与砜类顺利反应,以良好至高收率生产有价值的二苯乙烯和相关的 1,3-二烯衍生物,具有良好的官能团耐受性和优异的E选择性。利用该方法,还成功制备了具有生物活性的白藜芦醇和DMU-212,进一步证明了该反应的实用性。
Ion-supported PhI-catalyzed cyclization of N-methoxy-2-arylethanesulfonamides with mCPBA
摘要:
The ion-supported PhI-catalyzed cyclization of N-methoxy-2-arylethanesulfonamides with mCPBA was carried out to form the corresponding N-methoxy-3,4-dihydro-2,1-benzothiazine-2,2-dioxides in moderate to good yields in 2,2,2-trifluoroethanol. Here, reactive hypervalent iodine compounds, that is, ion-supported [(hydroxy)(tosyloxy)iodo]benzenes, were formed in situ and reacted with N-methoxy-2-arylethanesulfonamides to form the corresponding N-methoxy-3,4-dihydro-2,1-benzothiazine-2,2-dioxides in an electrophilic manner on the aromatic ring. Moreover, ion-supported Phi could be efficiently reused to provide the products in good yields. The same ion-supported PhI-catalyzed cyclization of N-methoxy-3-phenylpropionamide and N-methoxy-4-phenylbutyramide with mCPBA was carried out to form the corresponding N-methoxy benzolactams in moderate yields in 2,2,2-trifluoroethanol. (C) 2009 Elsevier Ltd. All rights reserved.
A transition-metal-free and base promoted C–C bond forming reaction of benzyl C(sp3)–H bond with organoammonium salts via C–N bondcleavage has been reported. Benzyl ammonium salts as well as cinnamyl ammonium salt could couple readily with various benzyl C(sp3)–H species, producing the corresponding products in moderate to excellent yields with good functional group tolerance. Late stage chemical