Reaction of carbonyl compounds with dimethyl 3‐ketoglutarate. Synthesis of bicyclic furan derivatives

Abstract

Acid catalyzed reaction of cyelododecane‐1,2‐dione VI with dimethyl,3‐ketoglutarate II led to the formation of methyl (E)‐6,7,8,9,10,11,12,13‐octahydro‐3‐(methoxycarbonyl)cyclododeca‐[b]furan‐2‐aeetate IX, presumably formed through the dihydrodihydroxy furan VIII. This dihydrofuran intermediate VIII was shown to be characteristic of the reaction of 2‐substituted carbonyl‐compounds with 11 for both α‐chlorocyclohexanone and α‐chlorocyclopentanone furnished furans XVIa and XX, respectively, when treated with 11. The effect of dihydrodihydroxy‐furan intermediates on the course of such reactions is discussed.

The Chemistry of α-Haloketones and Their Utility in Heterocyclic Synthesis

“…Condensation of α-haloketones with each of β-keto esters 241 and dimedone ( 243 ) affords the corresponding furans 242 [ 481 ] and 6,6-dimethyl-4-oxo-4,5,6,7-tetrahydrobenzofurans 245 , re-spect-ive-ly ( Scheme 72 ) [ 482 , 483 , 484 , 485 , 486 ].…”