87742-13-0Relevant articles and documents
Sulfite-driven, oxorhenium-catalyzed deoxydehydration of glycols
Ahmad, Irshad,Chapman, Garry,Nicholas, Kenneth M.
experimental part, p. 2810 - 2818 (2011/07/31)
Methyltrioxorhenium and perrhennate salts catalyze the deoxydehydration (DODH) of glycols by sulfite, producing olefins regiospecifically. The scope and efficiency of these reactions with respect to the polyol substrate, reducing agent, catalyst, solvents, and various additives are investigated. In general, MeReO3 is a more active catalyst for sulfite-driven DODH, but the Z+ReO4- derivatives (Z = Na, Bu4N) are more selective. Epoxides are also deoxygenated by Na2SO 3/MeReO3, but not by Bu4NReO4. The perrhenate catalysts also promote glycol DODH with other reductants, e.g., PR3, secondary alcohols, and ArSMe. The DODH reactions of 1,2-cyclohexanediol and (+)-diethyl tartrate occur with high syn-stereoselectivity. The polyol meso-erythritol is largely converted to 1,3-butadiene with minor amounts of 2-butene-1,4-diol and 2,5-dihydrofuran, indicating faster terminal glycol DODH. Stoichiometric reaction studies demonstrate the viability of a catalytic pathway involving (a) glycol condensation with MeReO3 to form MeReVIIO 2(glycolate); (b) O-transfer reduction of the ReVII- glycolate by sulfite or PR3 to produce [MeRevO(glycolate)] 2; and (c) thermal fragmentation of the reduced Re-glycolates to produce olefin (and regeneration of MeReO3).
