Unexpected cycloreversion of a tosylated sugar oxetane under E2 conditions: The facile formation of 2-(2-furanyl)-1, 3-dioxolane from a novel 2, 5:4, 6-dianhydro-L-idose derivative (Preliminary commun

• Published in: Journal of the Serbian Chemical Society 2004, Vol.69 (2), p.117-122
• Main Authors: Popsavin, Velimir, Radic, Ljubica, Popsavin, Mirjana, Cirin-Novta, Vera
• Format: Article
• Language: English
• Subjects: 2,5-anhydro-l-idose; 2,5:4,6-dianhydro-l-idose; cycloreversion; sugar oxetanes
• ISSN: 0352-5139; 1820-7421
• DOI: 10.2298/JSC0402117P

2,5:4,6-Dianhydro-3-O-p-toluenesulfonyl-L-idose ethylene acetal (4) was synthesized with the aim of studying its chemical behaviour in the presence of several basic agents (Bu4NF/MeCN, NaOMe/MeOH, KOBut/ButOH/THF, and NaH/DMSO). Treatment of 4 with sodium hydride in dimethyl sulphoxide at room temperature unexpectedly gave the 2-(2-furanyl)-1,3-dioxolane. The mechanism of the process presumably involved the initial conversion of 4 to the corresponding 2,3-unsaturated derivative 5, followed by a facile oxetane ring cycloreversion by the elimination of formaldehyde. Novi derivat 2,5:4,6-dianhidro-L-idoze 4 dobijen je visefaznim transformacijama D-glukoze, a zatim je ispitivano njegovo hemijsko ponasanje u prisustvu nekoliko baznih agenasa (Bu4NF/MeCN, NaOMe/MeOH,KOBut/ButOH/THF NaH/DMSO). Reakcijom jedinjenja 4 sa natrijum-hidridom u dimetilsulfoksidu neocekivano je dobijen 2-(2-furanil)-1,3-dioksolan (10). Predlozen je mehanizam ove neobicne transformacije, koji najverovatnije obuhvata inicijalni E2 eliminacioni proces, pracen naknadnim fragmentacionim otvaranjem oksetanskog prstena uz izdvajanje formaldehida.