Perhydrofuro pyran derivatives

Perhydrofuro[2,3- ]pytai derivatives can be synthesized in one pot via a reaction sequence involving addition and cyclization reactions. The reactants, dihydropyran and pyruvate esters, undergo a reaction which is mediated by Lewis acids such as TiCU, to afford perhydrofuro[2,3-/ ]pyran derivatives in good yields <2003SL1491>. 

Perhydrofuro[3,4-.i]pyrans can be prepared via a regioselective domino metathesis reaction of ally I- and propargyl-substituted oxanorbornenic esters, 129. The resulting /ra s-fmed perhydrofuro[3,4-/ ]pyran derivatives are formed in high yields <2000TL9777>. 

The diisobutylaluminium hydride (DIBAL-H) reduction of perhydrofuro[2,3- ]py derivatives, 58, is a novel entry to highly functionalized cyclopentanes containing high enantiomeric purity. The reduction targets the acetal group of the furo[2,3-/ ]pyran framework <2001CAR63>. 

Perhydrofuro[2,3- ]pyrans can be synthesized via a ring-opening reaction of sugar derivatives containing a 1,2-cyclopropyl group <20070L1331>. 

Sabitha et al. published an analogous reaction utilizing a D-glucose-derived aldehyde 337 for the construction of the Yonemitsu reaction product 338 (Scheme 13.75) [128]. The aldehyde 340 containing a free hydroxyl group directly led to a decarboxylative cyclization step with the Meldrum s acid moiety, subsequent to the formation of the Yonemitsu product providing 7-(l//-3-indolyl)-2,3-dimethoxy-perhydrofuro[3,2-b]pyran-5-ones 341 in good yields (74-84%). 

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