No abstract

Ring Enlargement by Lactonization of Methylated I -(3'-Hydroxypropyl)-2-oxocyclododerane-I-carbonitriI~sThe tillc compounds were prepii-ed by Michrrd reaction of 2-oxocyclododccanc-1 -carbonitrile (1) and acrylaldehyde and its derivatives lollowed by NaBH, reduction o r methylation of the aldehyde group withi S d i r m r /). I n all cases, thc ringeiilargenient was performed with Bu4NF!THF to give different methylated dei-ivatives of 12-cyano-I 5-pcntadecanolidc (13) in 95 -99% kield. The yields o f the rearrnngement products arc not dependent on the positions and nuinhers of the C H 3 groups in the side chain of 3. The IactoiiiLation reaction is of unremarkable stcreoscleclivity.

No abstract

A New Synthesis of ( f )-DihydrorecifeiolideEthyl I-(2'-formylethyl)-2-oxocyclooctane-l-carboxylate (2) prepared by Michuel reaction of ethyl 2-0x0-cyclooctane-I-carboxylate (1) was regioselectively methylated at the aldehyde group with (CH,)2TI[OCH(CH3)2]2 to give 3 (Scheme, 1 ) . The alcohol 3 was trcatcd with Hu4NF to give the deethoxycarbonylated product 4 which by distillation gave the bicyclic enol ether 5. Oxidation (m-chloroperbenzoic acid) of 5 and reduction of the resulting oxolacton 6 yielded the title compound ( + )-dihydrorecifeiolide (7) in an overall yield of nearly SO %. Methylation of the aldehyde 2 with MeLi gave the ring-enlargcd lacton 9 in poor yield (13%). The deethoxycarbonylation reaction 3 + 4 was studied in more detail (Scheme 3).