Evidence for formation of a Co-H bond from (H2O)2Co(dmgBF2)2 under H2: application to radical cyclizations.
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).
Department of Chemistry, Columbia University, 3000 Broadway, New York, New York 10027, USA.
Gang
G
Li
Arthur
A
Han
Mary E
ME
Pulling
Deven P
DP
Estes
Jack R
JR
Norton
D000466:Alkadienes / Q000737:chemistry; D003035:Cobalt / Q000737:chemistry*; D003500:Cyclization; D005609:Free Radicals / Q000737:chemistry; D006859:Hydrogen / Q000737:chemistry*; D009942:Organometallic Compounds / Q000737:chemistry*
D000466:Alkadienes; D005609:Free Radicals; D009942:Organometallic Compounds; D003035:Cobalt; D006859:Hydrogen