Synthesis of the precursors of iminosugars with 7-membered ring

d-Glucose was converted into the orthogonally protected open-chain derivative having different blocks at both terminal positions: C1 and C6. Selective deprotection of the C1-position opened a route to intermediate with the D-gluco-configuration, while deprotection at the C6-position gave the L-gulo isomer. In both derivatives, the oxime functionality was installed at the proper terminal position, which produced the corresponding precursors of a family of 7-membered ring iminosugars. One of these oximes was converted into the direct precursor: 6,1-bromonitrile.