is trans to the new carbon–carbon bond dominate (avg. ratio 98:2). These are obtained in 70–98 % ee (avg. 86 %; data for optimum R′ and R′′′), as determined by 1H NMR with the chiral solvating agent Λ‐(S ,S )‐2 3+ 2I−B(3,5‐C6H3(CF3)2)4−. NMR experiments show that the cyanoacetate and acetylenic esters and pyridine can hydrogen bond to certain NH groups of the catalyst. Rates are zero order in the cyanoacetate
的手性对映体纯
钴(III)络合物Δ-[CO((小号,小号)-DPEN)3 ] 3+ 2CL - B(C 6 ˚F 5)4 -(Δ-(小号,小号) - 2 3+ 2CL - B(C 6 ˚F 5)4 - ; DPEN = -1,2-二苯基
乙二胺)是一种有效的催化剂,与
吡啶一起(10摩尔%各)中,取代的
氰基
乙酸酯的对映体选择性的添加酯NCCH(R)CO 2 R',以炔属酯R''C≡CCO 2 R'''。在生成的加合物NC(R'O2 C)C(R)= CR''C CHCO 2 R''',C = C的异构体,其中,CO 2 R'''部分是反式到新的碳-碳键占据主导地位(平均比98:2 )。这些是由70–98%ee(平均86%;最佳R'和R'''的数据)获得的,这是通过1 H NMR和手性溶剂化剂Λ-(S,S)-2 3+ 2I确定的− B(3,5‐C 6 H 3(CF 3)2)4 −。NMR实验表明,