Highly regio- and stereoselective PdCl2(MeCN)2-catalyzed cross coupling of 1,2-allenylic sulfoxides with allyl bromide
作者:Shengming Ma、Qi Wei、Hongjun Ren
DOI:10.1016/j.tetlet.2004.02.144
日期:2004.4
2-Allyl-1(E),3(E)-dienyl sulfoxides were prepared highlystereoselectively via the PdCl2(MeCN)2-catalyzed coupling reaction of 1,2-allenylicsulfoxides and allyl bromide. A rationale was proposed for this transformation.
It was observed that the halohydroxylation of 1,2-allenyl sulfides or selenides with Br-2 (CuBr2 or NBS) or I-2 and water demonstrated a fairly good regioselectivity (i.e., the C=C bond that is remote from the S or Se atom was halohydroxylated with the halogen atom connecting to the middle carbon atom and the hydroxyl group connecting to the non-S terminal carbon or Se-substituted terminal carbon atom of the allene moiety), leading to the synthesis of synthetically important 3-organosulfur or seleno-2-haloallylic alcohols. The stereoselectivity depends on the nature of X+ and S or Se, showing a Z-selectivity with the matched Lewis acid-base pair.