Synthesis of chiral oxepanes and pyrans by 3-O-allylcarbohydrate nitrone cycloaddition (3-OACNC)
作者:Ashoke Bhattacharjee、Seema Datta、Partha Chattopadhyay、Nanda Ghoshal、Asish P Kundu、Arani Pal、Ranjan Mukhopadhyay、Sandip Chowdhury、Anup Bhattacharjya、Amarendra Patra
DOI:10.1016/s0040-4020(03)00634-3
日期:2003.6
3-O-Allylcarbohydrate nitrone cycloaddition (3-OACNC) furnished pyran and oxepane derivatives from 3-O-allyl hexose N-benzyl nitrones and 3-O-allyl furanoside-5-aldehyde N-benzyl/methyl nitrones. The regioselectivity of 3-OACNC was found to depend on the following factors (a) the structural nature of the nitrone (b) substitution and stereochemistry at 3-C of the carbohydrate backbone (c) substitution
3- ø从3- -Allylcarbohydrate硝酮环加成(3- OACNC)布置吡喃和氧杂环庚烷衍生物ø -烯丙基己糖ñ -苄基硝酮和3- ö烯丙基呋喃-5-醛ñ -苄基/甲基硝酮。发现3-OACNC的区域选择性取决于以下因素(a)硝酮的结构性质(b)碳水化合物主链在3-C处的取代和立体化学(c)在O末端的取代-烯丙基部分。从特定组的己糖硝酮和相应的呋喃糖苷硝酮获得的氧杂环丁烷或吡喃通过降解转化为对映体环状醚。在3- O-烯丙基碳水合物衍生的肟的分子内肟环烯烃加成反应(IOOC )中形成环氧丙烷和吡喃的混合物。