Convergent synthesis of fully functionalized ring C allocolchicinoids. Benzannulation approach.
[reaction: see text]. A novel convergent approach to fully functionalized ring C allocolchicinoids is developed which is based on the benzannulation reaction of Fischer carbene complexes with alkynes. The efficacy of this strategy was established with the conversion of bromide 1a (R1 = Me, R2 = H) to the biaryl phenol 3a (R = Me, R(L) = Pr, R(S) = H) via the carbene complex 2a. Bromide 1b (R1 = t-Bu, R2 = OMe) was then used for the analogous preparation of the diastereomeric allocolchicinoids 3b (R = Me, R(L) = Pr, R(S) = H).
Vorogushin
A V
AV
Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA.
Wulff
W D
WD
Hansen
H J
HJ
D003078:Colchicine / Q000031:analogs & derivatives / Q000138:chemical synthesis*; D013237:Stereoisomerism
D003078:Colchicine