Department of Chemistry, University of California, Berkeley, California 94720, United States.
J Am Chem Soc. 2010 Nov 24;132(46):16365-7. doi: 10.1021/ja107968c. Epub 2010 Oct 29.
The asymmetric C-H functionalization of norbornene and norbornadiene with five-, six-, and seven-membered cyclic enones mediated by the reactive intermediate [{η(5)-((t)BuMe(2)Si)C(5)H(4)}Co(NO)(2)] is reported. A novel base mixture derived from enantiopure ammonium salts and NaHMDS was used as a source of chirality, and this enantioselective desymmetrization of C(s) alkenes has been applied to the asymmetric synthesis of C(2)- and C(1)-symmetric diene ligands in high regioselectivity (3.7-20:1 anti/syn), near perfect diastereoselectivity (>99:1 dr), and high enantioselectivity (90-96% ee).
报道了通过活性中间体 [{η(5)-((t)BuMe(2)Si)C(5)H(4)}Co(NO)(2)]介导的降冰片烯和降冰片二烯与五元、六元和七元环环烯酮的不对称 C-H 官能化。使用源自手性铵盐和 NaHMDS 的新型碱混合物作为手性源,这种 C(s) 烯烃的对映选择性去对称化已应用于 C(2)-和 C(1)-对称二烯配体的不对称合成中,具有高区域选择性(3.7-20:1 反式/顺式)、近乎完美的非对映选择性(>99:1 dr)和高对映选择性(90-96%ee)。