Enantio- and Diastereoselectivity in the Intramolecular Cyclopropanation of Secondary Allylic Diazoacetates

Martin, Stephen F.; Spaller, Mark R.; Liras, Spiros; Hartmann, Benoît

doi:10.1021/ja00089a055

Cited by 102 publications

(27 citation statements)

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“…Here, we report a diastereo-and enantioselective tandem conjugate addition-aldol cyclization of enone-diones, whereby two COC bonds and four contiguous stereogenic centers are created in a single manipulation with control of relative and absolute stereochemistry (Scheme 1). Through the use of chiral racemic enone-dione substrates, the first examples of parallel kinetic resolutions (24) by enantioselective conjugate addition are achieved (25)(26)(27)(28)(29)(30)(31)(32)(33). This new catalytic methodology enables concise entry to seco-B ring steroids possessing a cis-fused C-D ring junction with a bridgehead hydroxyl residue, as found in naturally occurring cardiotonic steroids derived from digitalis.…”

mentioning

confidence: 99%

Desymmetrization of enone-diones via rhodium-catalyzed diastereo- and enantioselective tandem conjugate addition-aldol cyclization

Bocknack

Wang

Krische

2004

Proc. Natl. Acad. Sci. U.S.A.

131

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Catalytic tandem conjugate addition-enolate trapping represents an effective strategy for the design of catalytic transformations that enable formation of multiple COC bonds. Recently, using enantioselective rhodium-catalyzed conjugate addition methodology, we developed a catalytic tandem conjugate addition-aldol cyclization of keto-enones. Here, we report related desymmetrizations and parallel kinetic resolutions involving the use of diones as terminal electrophiles. The Rh-enolate generated on enone carbometallation effectively discriminates among four diastereotopic -faces of the appendant dione, ultimately providing products that embody four contiguous stereocenters, including two adjacent quaternary centers, with quantitative diastereoselection and high levels of enantiomeric excess. This methodology allows concise entry to optically enriched seco-B ring steroids possessing a 14-hydroxy cis-fused C-D ring junction, as found in naturally occurring cardiotonic steroids derived from digitalis.

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mentioning

confidence: 99%

Desymmetrization of enone-diones via rhodium-catalyzed diastereo- and enantioselective tandem conjugate addition-aldol cyclization

Bocknack

Wang

Krische

2004

Proc. Natl. Acad. Sci. U.S.A.

131

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“…The latter constituted a key intermediate in a total synthesis of natural biologically active product ambruticin S [197]. Furthermore, the reaction of secondary divinyldiazoacetate 212 led to the corresponding cyclopropane derivative 213 as a 50:50 mixture of two diastereomers each obtained in 94% ee and quantitative yield (Scheme 81) [198]. This mixture was further employed as key intermediate in the total synthesis of natural products, tremulenediol A and tremulenolide A [199], and to that of various cyclopropanederived peptidomimetics [200].…”

Section: (Scheme 79)mentioning

confidence: 99%

Applications of Chiral Three-membered Rings for Total Synthesis: A Review

Dalpozzo¹,

Lattanzi

Pellissier

2017

COC

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This review updates recent applications of asymmetric aziridination, azirination, thiirination, epoxidation, and cyclopropanation in the total synthesis of biologically active compounds, including natural products, using chiral substrates or chiral catalysts, covering the literature since 2000. The interest towards these synthetic methodologies of chiral three-membered rings has increased in the last decade, dictated either by the biological activities that display many naturally occurring products bearing a three-membered unit or by the ring strain of three-membered rings making them useful precursors of many more complex interesting molecules. Classic as well as modern protocols in asymmetric aziridinations, azirinations, epoxidations, thiirinations, and cyclopropanations have been widely applied as key steps of a number of syntheses of important products. Although the use of chiral substrates and auxiliaries is still highly employed particularly in asymmetric aziridination and cyclopropanation, the development of enantioselective catalytic methodologies has witnessed exponential growth during the last decade. The present review is subdivided into three parts, dealing successively with the use of chiral nitrogen-containing three-membered rings, chiral epoxides and thiiranes, and chiral cyclopropanes in total synthesis.

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“…[20] Racemic 9 was fully transformed into a mixture of isomeric cyclopropanes 10 and 11, each one derived from one enantiomer of 9. This is indicative that the two enantiomers of the catalyst should lead to products deriving from regioisomeric attack on the double bonds of the enantiopure 9.…”

Section: Regioselective Transformation On a Racemic Mixturementioning

confidence: 99%

“…Intramolecular cyclopropanation of a racemic diene catalyzed by a chiral rhodium complex. [20] Scheme 5. Regiodivergent reaction on a racemic mixture: intramolecular cyclopropanation (a) on (S)-12 and CÀH insertion (b) followed by ketene extrusion on (R)-12.…”

Section: Sharpless Epoxidationmentioning

confidence: 99%

Regioselective Reactions on a Chiral Substrate Controlled by the Configuration of a Chiral Catalyst

Kumar

Kagan

2010

Adv Synth Catal

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A racemic mixture may be partially transformed in the presence of a chiral catalyst by kinetic resolution and formation of products with new structural features. If the starting material is fully consumed the products may still be enantiomerically enriched. The situation is summarized in the Introduction. A brief discussion on the regioselective transformations occurring on a racemic mixture under the influence of a chiral catalyst is presented in Section 2. Often stereo-differences occur, each enantiomer of the starting material resulting in a different product. It allows one to predict what the behaviour of some enantiopure substrates should be in presence of each of the enantiomers of a chiral catalyst. Many examples are presented in Section 3. The chiral substrates under consideration have two different reacting sites, usually of the same nature (OH, C=C, allylic positions, C À H for carbene insertion, epoxide fragment, etc.). In some cases the absolute configuration of the catalyst allows an excellent control of the regioselectivity. This approach is promising for the selective transformation of chiral molecules.

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Enantio- and Diastereoselectivity in the Intramolecular Cyclopropanation of Secondary Allylic Diazoacetates

Cited by 102 publications

References 0 publications

Desymmetrization of enone-diones via rhodium-catalyzed diastereo- and enantioselective tandem conjugate addition-aldol cyclization

Desymmetrization of enone-diones via rhodium-catalyzed diastereo- and enantioselective tandem conjugate addition-aldol cyclization

Applications of Chiral Three-membered Rings for Total Synthesis: A Review

Regioselective Reactions on a Chiral Substrate Controlled by the Configuration of a Chiral Catalyst

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