Preparation of Vinylogous 2-Sulfonylindolines by the Palladium-Catalyzed Heteroannulation of <i>o</i>-Iodoanilines with Dienyl Sulfones and Their Further Transformation to Indoles and Carbazoles
作者:Thomas G. Back、Richard J. Bethell、Masood Parvez、Jerry A. Taylor
DOI:10.1021/jo016080m
日期:2001.12.1
employed as dienes in Diels-Alder reactions with dimethyl acetylenedicarboxylate (DMAD), methyl propiolate, or methyl acrylate. In the case of the latter two dienophiles, the cycloadditions were highly regioselective, affording the corresponding 1,3-products (with respect to the relative positions of the sulfone and ester groups), exclusively. The cycloadducts from acetylenic dienophiles were converted to
钯催化的邻二碘苯胺与二烯基砜的杂环化提供了一条方便的途径,以制备乙烯基2-磺酰二氮杂吲哚3。该反应在碳酸钾和催化乙酸钯(II)的存在下于DMF /水中进行,并且与电子-在苯胺的对位上有一个供体和撤去的取代基,并且在二烯基砜的C-2上有一个烷基取代基。将该二氢吲哚用DDQ进行氧化,得到相应的吲哚4。然后将其用作二炔与乙炔二羧酸二甲酯(DMAD),丙酸甲酯或丙烯酸甲酯的Diels-Alder反应中的二烯。对于后两个亲双烯体,环加成具有高度区域选择性,从而提供相应的1,3种产品(相对于砜和酯基的相对位置)。通过用DBU消除砜部分,将炔属双亲二烯体的环加合物转化为相应的咔唑,然后将丙烯酸甲酯的环加合物进行还原性脱磺酰化并用DDQ氧化为相应的咔唑。因此,该方法提供了在3-,4-和6-位具有各种取代基的咔唑的途径。