Novel preparation of 2,1-benzothiazine derivatives from sulfonamides with [hydroxy(tosyloxy)iodo]arenes
作者:Yuhta Misu、Hideo Togo
DOI:10.1039/b301330h
日期:2003.4.14
Cyclization of sulfonamides bearing an aromatic ring at the β-position with various organohypervalent iodine compounds was carried out to form the corresponding 2,1-benzothiazine derivatives. Among them, the cyclization effectively proceeded with [hydroxy(tosyloxy)iodo]arenes through ionic pathways. The same treatment of a sulfonamide bearing a 4-methoxyphenyl group at the β-position generated a spiro compound.
Ion-supported PhI-catalyzed cyclization of N-methoxy-2-arylethanesulfonamides with mCPBA
作者:Yoshihide Ishiwata、Hideo Togo
DOI:10.1016/j.tetlet.2009.07.034
日期:2009.9
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.
Iodoarene-Mediated Cyclization of N-Methoxy-2-arylethanesulfonamides with Oxone
作者:Hideo Togo、Yuhsuke Suzuki、Yoshihide Ishiwata
DOI:10.3987/com-10-s(e)4
日期:——
Iodoarene-mediated cyclization of N-methoxy-2-arylethanesulfonamides with Oxone (R) was carried out to form the corresponding N-methoxy-3,4-dihydro-2,1-benzothiazine-2,2-dioxides in moderate to good yields in acetonitrile. In this reaction, reactive hypervalent iodine species, i.e., [(hydroxy)(tosyloxy)iodo]arenes, 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. Ion-supported PhI could be also used for the same cyclization of N-methoxy-2-arylethanesulfonamides with Oxone to provide N-methoxy-3,4-dihydro-2,1-benzothiazine-2,2-dioxides in good to moderte yields. However, ion-supported PhI could not be reused for the same reaction. The same iodoarene-mediated cyclization of N-methoxy-3-phenylpropanamide and N-methoxy-4-phenylbutanamide with Oxone was also carried out to form the corresponding N-methoxybenzolactams in moderate yields.