RING ENLARGEMENT BY FRAGMENTATION. SYNTHESIS OF 15-PENTADECANOLIDE (EXALTOLIDE

Article abstract of DOI:10.1002/hlca.19870700324

The title compound was synthesized from 1-(3'-hydroxypropyl)-2-oxocyclododecane-1-carbonitrile (3), using two different routes (Scheme).The CN group of 3 was converted to the Me3N(1+) residue in 5 which underwent , upon NaH treatment, a fragmentation leading to the ring-enlargement product 6.Teh same product was observed after heating the ring-enlarged dimethylamine oxide 14, prepared from 3 bya Bu4NF treatment and conversion of the CN into the dimethylamine-oxide moniety.Ozonolysis of the methylidene double bond in 6 and reduction of the resulting C=O to a CH2 group gave Exaltolide<*> (8).