Regio- and stereoselectivity in Diels–Alder reactions of 1,2-disubstituted dienes with enantiopure (SS)-(p-tolylsulfinyl)-1,4-benzoquinones
作者:M.Carmen Carreño、José L Garcı́a Ruano*、Cynthia Z Remor、Antonio Urbano
DOI:10.1016/s0957-4166(00)00365-7
日期:2000.11
Reactions of 1,2-disubstituted dienes 1–3 with enantiopure sulfinylquinones 4–6 occur with similar π-facial diastereoselectivities but reversed regiochemistry under thermal conditions and in the presence of ZnBr2. After spontaneous elimination of the sulfoxide, optically active polycyclic dihydroquinones are formed with ees ranging from 36 to >97%. The regiochemistry of the process is controlled by
的1,2-二取代的二烯反应1 - 3与对映体纯sulfinylquinones 4 - 6发生类似π-面部非对映选择性,但在热条件下和在ZnBr存在反转区域化学2。自发消除亚砜后,形成旋光性多环二氢醌,其ee含量为36%至> 97%。该方法的区域化学由热反应中C-1处的烷基取代基控制,而在ZnBr 2存在下,C-2处的氧化功能成为主要控制者。