Evidence for formation of a Co-H bond from (H2O)2Co(dmgBF2)2 under H2: application to radical cyclizations

Gang Li; Arthur Han; Mary E Pulling; Deven P Estes; Jack R Norton

doi:10.1021/ja306037w

Evidence for formation of a Co-H bond from (H2O)2Co(dmgBF2)2 under H2: application to radical cyclizations

J Am Chem Soc. 2012 Sep 12;134(36):14662-5. doi: 10.1021/ja306037w. Epub 2012 Aug 27.

Authors

Gang Li¹, Arthur Han, Mary E Pulling, Deven P Estes, Jack R Norton

Affiliation

¹ Department of Chemistry, Columbia University, 3000 Broadway, New York, New York 10027, USA.

PMID: 22897586
DOI: 10.1021/ja306037w

Abstract

Under H(2), the radical cyclization of appropriate dienes can be catalyzed by cobaloximes. H• can be abstracted from an intermediate (presumably a cobalt hydride) by trityl radicals (Ar(3)C•) or by TEMPO. The rate-determining step in these reactions is the uptake of H(2), which is second order in cobalt and first order in hydrogen; the third-order rate constant is 106(3) M(-2)·s(-1).

Publication types

Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

Alkadienes / chemistry
Cobalt / chemistry*
Cyclization
Free Radicals / chemistry
Hydrogen / chemistry*
Organometallic Compounds / chemistry*

Substances

Alkadienes
Free Radicals
Organometallic Compounds
Cobalt
Hydrogen