Enantioselective Palladium-Catalyzed Diamination of Alkenes Using N‑Fluorobenzenesulfonimide

An enantioselective Pd-catalyzed vicinal diamination of unactivated alkenes using N-fluorobenzenesulfonimide as both an oxidant and a source of nitrogen is reported. The use of Ph-pybox and Ph-quinox ligands afforded differentially protected vicinal diamines in good yields with high enantioselectivities. Mechanistic experiments revealed that the high enantioselectivity arises from selective formation of only one of four possible diastereomeric aminopalladation products of the chiral Pd complex. The aminopalladation complex was characterized by X-ray crystallography.本文报道了以N-氟代苯磺酰亚胺（N-fluorobenzenesulfonimide）同时作为氧化剂与氮源，实现未活化烯烃的对映选择性钯催化邻位二胺化反应。使用Ph-pybox与Ph-quinox配体，可得到带有不同保护基的邻位二胺化合物，反应收率良好且对映选择性优异。机理实验结果显示，该反应的高对映选择性源于手性钯络合物的四种可能非对映异构胺钯化产物中仅选择性生成单一产物。研究通过X射线晶体衍射（X-ray crystallography）对该胺钯化络合物进行了表征。