Stereocontrolled routes to cis-hydroxyamino sugars. Part VII. A synthesis of holacosamine

Methyl 4,6-di-O-p-toluenesulfonyl-α-D-threo-hex-2-enopyranoside 4b reacts with methylamine at room temperature to displace the allylic sulfonate only, and the ethyl urethane of the resulting 4-N-methylamino sugar is cyclized with iodonium ion to give the 2-iodo-oxazolidinone, 13. This substance, upon treatment with sodium iodide in acetone, gives the 2,6-diiodide 14a. Deiodination, followed by base hydrolysis, gives the cis-hydroxyamino precursor, which upon N-acetylation and O-methylation affords the previously known holacosaminide 1b.