1370438-88-2Relevant academic research and scientific papers
On Ni catalysts for catalytic, asymmetric Ni/Cr-mediated coupling reactions
Liu, Xiang,Li, Xiaoyong,Chen, Yu,Hu, Yimin,Kishi, Yoshito
supporting information; experimental part, p. 6136 - 6139 (2012/05/07)
The importance of the Ni catalyst in achieving catalytic asymmetric Ni/Cr-mediated coupling reactions effectively is demonstrated. Six phenanthroline-NiCl2 complexes 1a-c and 2a-c and five types of alkenyl iodides A-E were chosen for the study, thereby demonstrating that these Ni catalysts display a wide range of overall reactivity profiles in terms of the degree of asymmetric induction, geometrical isomerization, and coupling rate. For three types of alkenyl iodides A-C, a satisfactory Ni catalyst(s) was found within 1a-c and 2a-c. For disubstituted (Z)-alkenyl iodide D, 2c was identified as an acceptable Ni catalyst in terms of the absence of Z → E isomerization and the degree of asymmetric induction but not in terms of the coupling rate. Two phosphine-based Ni catalysts, [(Me)3P]2· NiCl2 and [(cy)3P]2·NiCl2, were found to meet all three criteria for D. The bond-forming reaction at the C16-C17 position of palytoxin was used to demonstrate the usefulness of the Ni catalysts thus identified.
