Cobryketone Derived from Vitamin B12 via Palladium-Catalyzed Cleavage of the sp3–sp3 Carbon–Carbon Bond
journal contributionposted on 19.04.2013, 00:00 by Sylwester Kurcoń, Keith ó Proinsias, Dorota Gryko
Heptamethyl cobyrinate was transformed into hexamethyl 8-nor-cobyrinate. The crucial step involved the synthesis of new, vitamin B12 derived cobryketone via palladium-catalyzed cleavage of the sp3–sp3 carbon–carbon bond with the liberation of the ketone. The replacement of sp3 carbon atom with sp2 (CO) at the 8-position produces a bathochromic shift of all absorption bands and makes α and β bands equal as a consequence of the expansion of the existing conjugated system of double bonds.