NOVEL [1,N]-CARBON TO CARBON REARRANGEMENT OF AN ESTER GROUP VIA ORGANOTITANIUM INTERMEDIATES WHEREIN THE N VARIES FROM 2 TO 5 - FULL SCOPEAND LIMITATION LEADING PREDOMINANTLY TO THE REARRANGEMENT

Malonates and methanetricarboxylates having an unsaturated side chain such as 2, 12, 20, 22, 24, 31, or 37 underwent a new ester rearrangeme nt reaction promoted by (eta(2)-propene)Ti(O-i-Pr)(2) to afford the su ccinate derivative 4 or alpha,beta-unsaturated ester 17, 21, 23, 25, 3 4, or 38 via the migration of the eater group from its original bis- o r tris-ester position to the acetylene- or olefin-titanium complex. It has been found that the side reactions competing with the desired mig ration are dealkylation of the side chain of the ester and a simple cy clization. The substrates and conditions which allow the ester migrati on a preferential path were determined as well as the scope and limita tion of this reaction.