Description:
<jats:title>Abstract</jats:title><jats:p>4‐<jats:italic>C</jats:italic>‐Formylglucopyranoside <jats:bold>9</jats:bold> was readily obtained from 4‐<jats:italic>O</jats:italic>‐unprotected glucose derivative <jats:bold>4</jats:bold> in four steps, each step giving a high product yield. Reaction with 1‐<jats:italic>C</jats:italic>‐lithiated 2‐phenylsulfinyl‐<jats:sc>D</jats:sc>‐galactal <jats:bold>10</jats:bold> as nucleophile furnished <jats:italic>C</jats:italic>‐disaccharide intermediates <jats:bold>11a</jats:bold> and <jats:bold>11b</jats:bold> as diastereoisomers. Ensuing removal of the phenylsulfinyl group with Raney nickel and regio‐ and diastereospecific 2b‐hydrogen and 3b‐hydroxy transfer afforded β(1–4)‐connected <jats:italic>C</jats:italic>‐lactosides <jats:bold>13a</jats:bold> and <jats:bold>13b</jats:bold>, respectively; their structures were deduced from derivatives <jats:bold>14a, b</jats:bold> and <jats:bold>16a, b</jats:bold> on the basis of <jats:sup>1</jats:sup>H‐NMR data. Hydrogenolytic <jats:italic>O</jats:italic>‐debenzylation of <jats:bold>13a</jats:bold> and <jats:bold>13b</jats:bold> afforded hydroxymethylene‐bridged <jats:italic>C</jats:italic>‐lactose <jats:bold>2a</jats:bold> and <jats:bold>2b</jats:bold>, respectively. Regioselective <jats:italic>O</jats:italic>‐benzylation of <jats:bold>13a</jats:bold> gave preferentially 1b‐<jats:italic>O</jats:italic>‐unprotected derivative <jats:bold>17aa</jats:bold> which furnished upon oxidation carbonyl‐bridged <jats:italic>C</jats:italic>‐lactose derivative <jats:bold>19</jats:bold>. Deoxygenation at <jats:italic>C</jats:italic>‐1b of <jats:bold>17aa</jats:bold> and subsequent hydrogenolytic <jats:italic>O</jats:italic>‐debenzylation furnished methylene‐bridged <jats:italic>C</jats:italic>‐lactose <jats:bold>1</jats:bold>.</jats:p>