200621-47-2Relevant academic research and scientific papers
A Ru catalyzed divergence: Oxidative cyclization vs cycloisomerization of bis-homopropargylic alcohols
Trost, Barry M.,Rhee, Young Ho
, p. 2528 - 2533 (2007/10/03)
During the course of investigating the development of catalytic reactions involving ruthenium vinylidene intermediates, a novel divergence of reactivity was discovered. The oxidative cyclization of bis-homopropargylic alcohols with Ru(+2) complexes as catalysts and N-hydroxysuccinimide as oxidant, which requires formation of a ruthenium vinylidene intermediate, is complicated by the simple electrophilically initiated direct attack of the hydroxyl group on π-complex of the alkyne and ruthenium. A catalytic system composed of CpRu[(p-CH3O6H4)3P]2Cl and excess (p-CH3O-C6H4)3P directs the reaction toward the oxidative cyclization to form δ-lactones in good yields. Significantly, a simple switch of catalyst to CpRu[(p-FC6H4)3P]2Cl redirects the reaction to a cycloisomerization to form dihydropyrans in good yields. The synthetic utility of the oxidative cyclization is illustrated by the synthesis of oviposition attractant pheromone of the mosquito Culex pipens. The utility of the cycloisomerization to dihydropyrans is demonstrated by an iterative process leading to the antiviral agent narbosine B. A rationale for this dramatic switch by simple ligand modification is proposed.
C-Glycosides to fused polycyclic ethers
Allwein, Shawn P.,Cox, Jason M.,Howard, Brett E.,Johnson, Henry W.B.,Rainier, Jon D.
, p. 1997 - 2009 (2007/10/03)
This manuscript describes the synthesis of fused polycyclic ethers from the coupling of C-glycoside forming reactions with ring closing metathesis and acid mediated annulation reactions.
A highly efficient iterative approach to fused ether ring systems
Rainier, Jon D.,Allwein, Shawn P.
, p. 9601 - 9604 (2007/10/03)
An iterative synthesis of fused ether ring systems has been developed. This strategy couples a cyclic enol ether oxidation and carbon-carbon bond forming reaction in one flask with an acid catalyzed cyclic acetal formation and alkoxide elimination in another flask. The result is a general and highly efficient two flask synthesis of fused ethers as are present in a wide variety of bioactive natural products.
A Novel Approach Towards cis- and trans-Fused Pyranopyrans Based on Ring-Closing Metathesis Reaction of Carbohydrate Derivatives
Leeuwenburgh, Michiel A.,Overkleeft, Herman S.,Van Der Marel, Gijsbert A.,Van Boom, Jacques H.
, p. 1263 - 1264 (2007/10/03)
A novel synthesis of both cis- and trans-fused pyranopyran systems, based on ring-closing metathesis of glycal derived dienes, is described. Isomerisation of the resulting allylic double bond provides a new cyclic enol ether, thus opening the way to an iterative synthesis of cis-(trans-)fused cyclic polyethers.
