Cobryketone Derived from Vitamin B₁₂ <i>via</i> Palladium-Catalyzed Cleavage of the sp³–sp³ Carbon–Carbon Bond

Heptamethyl cobyrinate was transformed into hexamethyl 8-<i>nor</i>-cobyrinate. The crucial step involved the synthesis of new, vitamin B₁₂ derived cobryketone <i>via</i> palladium-catalyzed cleavage of the sp³–sp³ carbon–carbon bond with the liberation of the ketone. The replacement of sp³ carbon atom with sp² (CO) 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

Vitamin B₁₂ Catalyzed Atom Transfer Radical Addition

Vitamin B₁₂, a natural Co-complex, catalyzes atom transfer radical addition (ATRA) of organic halides to olefins. The established conditions were found to be very selective, with atom transfer radical polymerization (ATRP) occurring only in the case of acrylates

Photoinduced Vitamin B₁₂-Catalysis for Deprotection of (Allyloxy)­arenes

Vitamin B₁₂ is a natural cobalt complex that, while reduced to the “supernucleophilic” Co­(I) form, can easily react with electrophiles via an S_N2 mechanism. It is also shown to react via an S_N2′ mechanism with allylic compounds allowing for photochemical deprotection of (allyloxy)­arenes. A sustainable alternative to commonly used noble metal-catalyzed deprotection reactions is presented