135500-31-1Relevant articles and documents
Synthesis of PDE IVb Inhibitors. 1. asymmetric synthesis and stereochemical assignment of (+)- and (-)-7-[3-(Cyclopentyloxy)-4-methoxyphenyl]hexahydro-3H- pyrrolizin-3-one
Sukhorukov, Alexey Yu.,Boyko, Yaroslav D.,Ioffe, Sema L.,Khomutova, Yulia A.,Nelyubina, Yulia V.,Tartakovsky, Vladimir A.
experimental part, p. 7893 - 7900 (2011/11/30)
Asymmetric synthesis of Glaxo Smith Kline's highly potent phosphodiesterase inhibitor 1 has been accomplished in nine steps and 16% overall yield. The original strategy suggested involves as a key step the silylation of enantiopure six-membered cyclic nit
A systematic investigation of quaternary ammonium ions as asymmetric phase-transfer catalysts. Synthesis of catalyst libraries and evaluation of catalyst activity
Denmark, Scott E.,Gould, Nathan D.,Wolf, Larry M.
experimental part, p. 4260 - 4336 (2011/07/09)
Despite over three decades of research into asymmetric phase-transfer catalysis (APTC), a fundamental understanding of the factors that affect the rate and stereoselectivity of this important process are still obscure. This paper describes the initial stages of a long-term program aimed at elucidating the physical organic foundations of APTC employing a chemoinformatic analysis of the alkylation of a protected glycine imine with libraries of enantiomerically enriched quaternary ammonium ions. The synthesis of the quaternary ammonium ions follows a diversity-oriented approach wherein the tandem inter[4 + 2]/intra[3 + 2] cycloaddition of nitroalkenes serves as the key transformation. A two-part synthetic strategy comprised of (1) preparation of enantioenriched scaffolds and (2) development of parallel synthesis procedures is described. The strategy allows for the facile introduction of four variable groups in the vicinity of a stereogenic quaternary ammonium ion. The quaternary ammonium ions exhibited a wide range of activity and to a lesser degree enantioselectivity. Catalyst activity and selectivity are rationalized in a qualitative way on the basis of the effective positive potential of the ammonium ion.
Desymmetrization of 1,4-dien-3-ols and related compounds via Ueno-Stork radical cyclizations
Villar, Felix,Equey, Olivier,Renaud, Philippe
, p. 1061 - 1063 (2007/10/03)
Desymmetrization of 1,4-dien-3-ols and related compounds via Ueno-Stork radical cyclizations is reported. The stereochemistry of the cyclization is controlled by the acetal center. Excellent stereocontrol at C(4) and C(5) of the newly formed tetrahydrofuran rings is observed. Use of a chiral auxiliary allows the preparation of enantiomerically pure material. The utility of this method has been demonstrated by achieving a short synthesis of (+)-eldanolide, the pheromone of the male African sugarcane stem borer Eldana saccharina.
Tandem Inter /Intra Nitroalkene Cycloadditions. 5. Origin of the Lewis Acid Dependent Reversal of Stereoselektivity
Denmark, Scott E.,Schnute, Mark E.,Senanayake, C. B. W.
, p. 1859 - 1874 (2007/10/02)
The stereochemical course of the tandem / nitroalkene cycloaddition with chiral enol ethers has been shown to exhibit remarkable sensitivity to the nature of the Lewis acid promoter.Cycloadditions using (+)-camphor-derived vinyl ether 3 or (-)-t
