A Convergent Strategy for the Synthesis of β-Carba-galacto-disaccharides

A convergent strategy for the synthesis of β-carba-galacto-disaccharides is illustrated by the preparation of <b>1</b> and <b>4</b>, from a central “glycone” component <b>22</b>, and the corresponding “aglycone” segments, monosaccharide alcohols, <b>23a</b> or <b>23b</b>. The key step is the formation of the carbasugar ring via an oxocarbenium ion−enol ether cyclization