Stereoselective syntheses of 2-subtituted perhydrofuro[2,3b]furans

New reagents for the stereoselective synthesis of 2-substituted perhydrofuro[2,3b]furanas are described. Ia the successful approach towards the latter compounds, the key steps were the addition of a aonolithio-2α-methoxy-3β-[(phenylsulfonyl)-methyilperhydrofuran to an aldehyde and a dilithio-2α-methoxy-3β-[(pheaylsulfonyl)-methyl]perhydrofuran to a carboxy1 derivative, respectively. The structures and conformations of the 2-tert-butylmtyl- and...