Asymmetric Synthesis Using Organometallic Reagents and Optically Pure Vinylic Sulfoxides
نویسنده
چکیده
A new, general method is developed for preparation of various 3-substituted carbonyl compounds of very high optical purity. Application of this method is made to asymmetric synthesis of either enantiomer of 3—methylalkanoic acids, of optically pure 3-methylcyclopentanone, 3—methylcyclohexanone, 3-naphthylcyclopentanone and 3-vinylcyclopentanone j. 9,11-Seco steroid and steroid intermediate are precursors of optically pure steroidal equilenin and estrone of natural absolute configuration. The basis for this asymmetric synthetic method rests on the transfer of chirality from the sulfoxide sulfur atom to the s-carbon carbon atom during organometallic s-addition to optically pure o-carbony1 c, -ethylenic sulfoxides.
منابع مشابه
Stereoselective Synthesis of α-Arylalkylamines by Glycosylation-induced Asymmetric Addition of Organometallic Compounds to Imines
Arylalkylamines are of interest as building blocks for the synthesis of biologically active compounds and as chiral ligands or chiral auxiliaries in stereoselective syntheses [1]. Their stereoselective synthesis has been achieved by enantioselective reduction of ketimines using chiral reagents [2], as for example Corey’s oxaborolidines [3], or proline-derived triacyloxyborohydrides [4]. Particu...
متن کاملCatalytic asymmetric alkylation of ketones using organometallic reagents.
The catalytic asymmetric synthesis of tertiary alcohols by the addition of organometallic reagents to ketones is of central importance in organic chemistry. The resulting quaternary stereocentres are difficult to prepare selectively by other means despite their widespread occurrence in natural products and pharmaceuticals. Over the past few years, several seminal reports on the formation of chi...
متن کاملA C(2)-symmetric chiral bis-sulfoxide ligand in a rhodium-catalyzed reaction: asymmetric 1,4-addition of sodium tetraarylborates to chromenones.
A new C(2)-symmetric chiral bis-sulfoxide ligand, (R,R)-1,2-bis(tert-butylsulfinyl)benzene, has been designed and prepared by the reaction of (R)-benzyl tert-butylsulfoxide with (R)-thiosulfinate. This ligand exhibits excellent enantioselectivities in the Rh-catalyzed asymmetric 1,4-addition reaction. In particular, the present work has realized access to optically pure flavanones for the first...
متن کاملSwitch in regioselectivity of epoxide ring-opening by changing the organometallic reagent.
The regio- and stereoselective ring-opening of a 2-(2'-oxiranyl)-1,2,3,6-tetrahydropyridine using organometallic reagents is reported. The choice of the organometallic reagent determines the formation of either 2-[(R)-1-hydroxyalkyl]- or 2-[(S)-2-hydroxy-1-alkyl]-1,2,3,6-tetrahydropyridines. The formation of 2-[(S)-2-hydroxy-1-alkyl]-1,2,3,6-tetrahydropyridines is a rare example of epoxide ring...
متن کاملRecent applications of polymer supported organometallic catalysts in organic synthesis.
Recent developments concerning the application of polymer supported organometallic reagents in solid phase synthesis are reviewed, with a special focus on methodology for carbon-carbon formation. Examples of reactions that are covered include the classical Suzuki, Sonogashira and Heck coupings, but also aryl amination, epoxide opening, rearrangements, metathesis and cyclopropanation. Applicatio...
متن کامل