55862-21-0Relevant articles and documents
Murai et al.
, p. 864 (1976)
Dibutyltin oxide mediated diastereoselective cyclodehydration/sulfonylation of 1,2,4-triols
Gamedze, Makhosazana P.,Nkambule, Comfort M.
, p. 1825 - 1829 (2015/03/30)
Dibutyltin oxide (Bu2SnO) mediated cyclodehydration or sulfonylation of 1,2,4-triols is predictably diastereoselective depending on the steric bulk of the substituents at C4. A larger difference (ΔA-value >1 kcal/mol) leads to the syn-1,2,4-triols favouring cyclodehydration (78-85%) to form 3-hydroxytetrahydrofurans, with the anti-1,2,4-triols favouring monosulfonylation (66-87%). Triols from symmetrical ketones preferentially undergo cyclodehydration in high yield (>75%) due to a gem-disubstituent effect. Thus, the 1,2,4-triols derived from simple cyclic ketones also favour cyclodehydration to form spirocyclic 3-hydroxytetrahydrofurans in 72-79% yields.
