NOVEL SQUALESTATIN DERIVATIVES ARISING FROM REACTIONS AT THE ALLYLIC CENTER OF THE C1-SIDE CHAIN

Reaction of 2 with Ac2O-TMSOTf gives the triacetate 5, which on furthe r reaction gives isomer 6, arising from an allylic rearrangement, wher eas reaction of 2 with Et3SiH-TMSOTf gives tricycle 7 arising from add ition of the C7-OH to the allylic centre, Attempted ionic reduction of triacetate 5 gives benzocyclo-heptene 8, arising from Friedel-Crafts alkylation of the phenyl ring by the allylic centre, Similar alkylatio n has been obtained with analogue 9, and with the trifluoromethanesulf onate ester of the allylic alcohol 13, Attempted ionic reduction of 17 , lacking the allylic centre, gives 20 arising from ester hydrolysis a t C4.