Stereocontrolled Reduction of 2-(<i>p</i>-Tolylsulfinyl)cycloalkanones under Basic Conditions: π-Facial Selection in Cyclic Systems Directed by a Chiral Side Chain
作者:Katsuyuki Ogura、Michio Ishida、Makoto Fujita
DOI:10.1246/bcsj.62.3987
日期:1989.12
Reduction of a 2-(p-tolylsulfinyl)cycloalkanone with sodium borohydride in methanol–triethylamine is accompanied by rapid epimerization at C2. Under the conditions employed here, the π-facial selectivity of the reduction is directed by the side chain chirality and, among four possible isomers of the corresponding cycloalkanol, one isomer is given with high selectivities up to 85%.
Synthesis and reduction of chiral sulfinyl cyclohexanones
作者:M.C. Carreño、J.L.García Ruano、A. Rubio
DOI:10.1016/s0040-4039(00)96645-0
日期:1987.1
The reaction of cyclohexanone with (S)-(−)-menthyl-p-toluenesulfinate in the presence of Pri2NMgBr yields a mixture of enantiomerically pure 2-p-tolylsulfinylcyclohexanone diastereoisomers. Their stereoselective reduction to chiral hydroxysulfoxides is also reported.
Stereoselective hydride reductions of chiral 2-p-tolylsulfinylcycloalkanones
作者:Ana B. Bueno、M. Carmen Carreño、Jose L. García Ruano、Begoña Peña、Almudena Rubio、Miguel A. Hoyos
DOI:10.1016/s0040-4020(01)85512-5
日期:——
The highly stereoselective hydride reductions of chiral 2-p-tolylsulfinyl-cyclopentanones and cycloheptanones are described. With DIBAL (electrophilic hydride) the configuration induced at C-1 is controlled by the sulfinyl group (1,3-asymmetric induction), and it can be inverted by using ZnCl2 as catalyst. With L-selectride the stereoselectivity is directed by the C-2 chiral groups (1,2-asymmetric induction). Other nucleophilic hydrides gave results which depend on the reagents and the size of the rings.