Reactions related to coenzyme B12 dependent rearrangements: Metal mediated free radical acyl migrations in methyl and cyclopropyl substituted models
✍ Scribed by Wayne M. Best; David A. Widdowson
- Publisher
- Elsevier Science
- Year
- 1989
- Tongue
- French
- Weight
- 806 KB
- Volume
- 45
- Category
- Article
- ISSN
- 0040-4020
No coin nor oath required. For personal study only.
✦ Synopsis
Free radicals generated from the methylmalonylcoenzyme A mutase model substrates (3) and (4) by chromium(ll) reduction, or by pyrolysis of the analogous cobaloximes, underwent [1,2]-migration only in the acyl series (R = Ph, Me) and not the critical ester series (R = OEt, SBu). The mechanism of the migration was implied by incorporation into (4) of the cyclopropyl ring, the opening of which demonstrated the free radical nature of the rearranged intermediate.
In continuation of our studies on rearrangements related to B,, catalysed reactions', we have examined substances which are intended to mimic the free radical methylmalonylCoA (1, R = H) -succinylCoA
(2, R = H) rearrangement (Scheme 1)2 but avoid the problems that we had previously encountered with tin based propagation steps'.