The Lewis acid (2-propoxy)titanium trichloride is an efficient reagent for epoxide-initiated polyene cyclisations. Thus, 4 underwent tricyclisation to yield tricyclic products 5–7 in 73 % yield. The tetraene epoxide 1 gave pentacycle 15 in 21 % yield. The latter is the first example of a cationic pentacarbocyclisation.
No takes yet. Share an insight, caveat, or question.
Fish et al. (1993) studied this question.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: