Abstract: While chain-walking stimulates wide interest in both
polymerization and organic synthesis, site- and stereoselective
control of chain-walking on rings is still a challenging task in the realm
of organometallic catalysis. Inspired by a controllable chain-walking
on cyclohexane rings in olefin polymerization, we have developed a
set of chain-walking carboborations of cyclcohexenes based on nickel
catalysis. Different from the 1,4-trans-selectivity disclosed in polymer
science, a high level of 1,3-regio- and cis-stereoselectivity is obtained
in our reactions. Mechanistically, we discovery that the base affects
the reduction ability of B2pin2 and different bases lead to different
catalytic cycles and different regioselective products (1,2- Vs 1,3-
addition). This study provides a concise and modular method for the
synthesis of 1,3-disubstituted cyclohexylboron compounds. The
incorporation of a readily modifiable boronate group greatly enhances
the value of this method, the synthetic potential of which was
highlighted by the synthesis of a series of high-valued commercial
chemicals and pharmaceutically interesting molecules.