Electrooxidative tricyclic 6-7-6 fused-system domino assembly to allocolchicines by a removable radical strategy.

Natural allocolchicine and analogues derived thereof a tricyclic 6-7-6-system have been found as key scaffold of various biologically relevant molecules. However, the direct preparation of the allocolchicine motif remains difficult to date. Herein, we report on an electrooxidative radical cyclization of biarylynones with various carbon- and heteroatom-centered radical precursors a sequential radical addition/7-/radical cyclization domino reaction.

Dibenzocycloheptanones construction through a removable -centered radical: synthesis of allocolchicine analogues.

Dibenzocycloheptanones containing a tricyclic 6-7-6-system are present in numerous biologically active natural molecules. However, the simple and efficient preparation of derivatives containing a dibenzocycloheptanone scaffold remains difficult to date. Herein, we report a versatile strategy for the construction of these challenging seven-membered rings using a 7--trig cyclization which is initiated by a phosphorus-centered radical.