3 research outputs found
Cobryketone Derived from Vitamin B<sub>12</sub> <i>via</i> Palladium-Catalyzed Cleavage of the sp<sup>3</sup>āsp<sup>3</sup> CarbonāCarbon Bond
Heptamethyl
cobyrinate was transformed into hexamethyl 8-<i>nor</i>-cobyrinate.
The crucial step involved the synthesis
of new, vitamin B<sub>12</sub> derived cobryketone <i>via</i> palladium-catalyzed cleavage of the sp<sup>3</sup>āsp<sup>3</sup> carbonācarbon bond with the liberation of the ketone.
The replacement of sp<sup>3</sup> carbon atom with sp<sup>2</sup> (Cī»O)
at the 8-position produces a bathochromic shift of all absorption
bands and makes Ī± and Ī² bands equal as a consequence of
the expansion of the existing conjugated system of double bonds
Vitamin B<sub>12</sub> Catalyzed Atom Transfer Radical Addition
Vitamin B<sub>12</sub>, 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 B<sub>12</sub>-Catalysis for Deprotection of (Allyloxy)Āarenes
Vitamin B<sub>12</sub> is a natural
cobalt complex that, while
reduced to the āsupernucleophilicā CoĀ(I) form, can easily
react with electrophiles via an S<sub>N</sub>2 mechanism. It is also
shown to react via an S<sub>N</sub>2ā² mechanism with allylic
compounds allowing for photochemical deprotection of (allyloxy)Āarenes.
A sustainable alternative to commonly used noble metal-catalyzed deprotection
reactions is presented