A spirocyclopropyl analogue of deoxyrhamnojirimycin has been synthesized in 11 steps and 20% overall yield from l-arabinose. The key step of the reaction path involves titanium-mediated aminocyclopropanation of an l-arabinononitrile derivative. Improvements of the standard reaction conditions were investigated. The use of methyltitanium triisopropoxide as the titanium source allowed the reaction to take place at room temperature and afforded the corresponding cyclopropylamine in 80% yield.
glycosidases - imino sugars - metallacycles - nitriles - spiro compounds - titanium