Metal trifluoromethanesulfonate-catalyzed regioselective borane-reductive ring opening of benzylidene acetals: a concise synthesis of 1,4-dideoxy-1,4-imino-L-xylitol.

[reaction: see text] A highly regioselective borane-reductive ring opening of the 4,6-O-benzylidene-D-hexopyranosides to the corresponding 6-alcohols in excellent yields at room temperature via various metal trifluoromethanesulfonates as catalysts is described here. Its application in the synthesis of 1,4-dideoxy-1,4-imino-L-xylitol is also highlighted.