Synthesis of 14-Membered Lactones from Cyclooctanone

As shown in the Scheme, 3-(1-nitro-2-oxocyclooctyl)propanal ( 1 ) prepared earlier from cyclooctanone was converted into the 14-membered lactones 6 and 7 . The aldehyde 1 was submitted to allylation to give 2 using allyltitnium or allylsilicon reagents. After lactonizatrion and transformation of the C,C-double bond to an alcohol, 4 was translactonized under acidic conditions to form 5 , from which 6 and 7 were prepared.