Catalytic Asymmetric Allylic and Homoallylic Diamination of Terminal Olefins via Formal C-H Activation

摘要

Metal-promoted diamination of olefins provides an effective approach to the synthesis of vicinal diamines, which are present in various biologically active molecules and are used as chiral control elements in asymmetric synthesis. Various diamination systems have been developed. Recently, we reported a Pd(0) and Cu(I)-catalyzed regio- and stereoselective diamination of conjugated dienes and trienes using di-terf-butyldiaziridinone (2) as nitrogen source. We have also shown that readily available terminal olefins can be diastereoselectively diaminated at allylic and homoallylic carbons via formal C-H activation with Pd(PPh_3)_4 (Scheme 1). Considering its synthetic potential, it is highly desirable to develop an asymmetric process for this diamination. Compared to asymmetric diamination of conjugated dienes as reported earlier, the current formal C-H diamination requires a catalyst system which will be able to effectively convert the terminal olefin into a conjugated diene in situ besides being enantioselective. Herein we wish to report our preliminary progress on this subject.