SYNTHESIS AND CHARACTERIZATION OF (5'-DEOXYADENOSIN-5'-YL)COBALAMIN (= ADENOSYLCOBALAMIN) ANALOGS MIMICKING THE TRANSITION-STATE GEOMETRY OF COENZYME-B-12-DEPENDENT REARRANGEMENTS

A convergent synthesis of the five novel analogues 1a-e of (5'-deoxyad enosin-5'-yl)cobalamin (= 'adenosylcobalamin') is described. The analo gues 1a-e carry oligomethylene chains (C3-C-7) inserted between the ce ntral Co-atom and the 5'-O-atom of the adenosine moiety and are though t to mimick the transition-state geometry in coenzyme-B,2-catalyzed re arrangement. All five analogues were characterized by NMR, UV, and FAB mass spectrometry.