Premium
An Alternative Synthesis of Cycloalkyl‐Substituted CPA Catalysts and Application in Asymmetric Protonation Reactions **
Author(s) -
McLean Liam A.,
Watson Allan J. B.
Publication year - 2021
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.202100980
Subject(s) - chemistry , protonation , negishi coupling , reagent , catalysis , aryl , combinatorial chemistry , organic chemistry , alkyl , ion
Abstract An alternative synthesis of cycloalkyl‐substituted CPA catalysts is reported. A Negishi coupling offers improved yields and purity of the necessary 1,3,5‐tri(cycloalkyl)benzenes. Limitations in the use of commercial organozinc reagents have been identified and a robust procedure for the preparation of these reagents is detailed. Similarly, a robust procedure for the key Kumada coupling is also provided. The route is demonstrated by preparation of three different tri(cycloalkyl)aryl‐substituted CPAs and the utility of these catalysts in asymmetric protonation reactions is shown.