摘要:
A new process for the efficient regioselective formation of 1,8,13,16-tetraoxadispiro[5.0.5.4]hexadecanes (dispiroketals) of various D-elucopyranosyl substrates by the chiral recognition of enantiomeric trans 1,2-diol relationships is described. This was achieved using the novel enantiomerically pure 2,2'-disubstituted 3,3',4,4'-tetrahydro-6,6'-bi-2H-pyrans 1, 2 and 11. New conditions for the removal of dispiroketal protecting groups are presented.