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Journal ArticleDOI

A new golden age for donor-acceptor cyclopropanes.

26 May 2014-Angewandte Chemie (WILEY‐VCH Verlag)-Vol. 53, Iss: 22, pp 5504-5523
TL;DR: This Review highlights the appropriate tools for successfully employing donor-acceptor cyclopropanes in ring-opening reactions, cycloadditions, and rearrangements.
Abstract: The effective use of ring strain has been applied to considerable advantage for the construction of complex systems. The focus here is directed towards cyclopropanes as building blocks for organic synthesis. Although thermodynamics should take the side of synthetic chemists, only a specific substitution pattern at the cyclopropane ring allows for particularly mild, efficient, and selective transformations. The required decrease in the activation barrier is achieved by the combined effects of vicinal electron-donating and electron-accepting moieties. This Review highlights the appropriate tools for successfully employing donor–acceptor cyclopropanes in ring-opening reactions, cycloadditions, and rearrangements.
Citations
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Journal ArticleDOI
TL;DR: This review summarizes research directed towards the formation of carbocyclic adducts from donor-acceptor cyclopropanes and focuses on annulation and cycloaddition reactions mediated by Lewis or protic acid, bases, or thermal conditions.
Abstract: This review summarizes research directed towards the formation of carbocyclic adducts from donor–acceptor cyclopropanes. The focus of the review is on annulation and cycloaddition reactions (both inter- and intramolecularly) mediated by Lewis or protic acid, bases, or thermal conditions. Rearrangements resulting in carbocycles and those reactions mediated by transition metal catalysis have been excluded.

366 citations

Journal ArticleDOI
TL;DR: An overview of the most important and widely used cyclopropanation techniques is presented, followed by a discussion of elegant approaches and clever solutions that have been developed to enable the synthesis of various uniquecyclopropane natural products or use of cycloprostanes as versatile strategic intermediates.
Abstract: Complex molecular architectures containing cyclopropanes present significant challenges for any synthetic chemist. This review aims to highlight the strategic considerations for introduction of the cyclopropane motif in a collection of recent total syntheses. At first, an overview of the most important and widely used cyclopropanation techniques is presented, followed by a discussion of elegant approaches and clever solutions that have been developed to enable the synthesis of various unique cyclopropane natural products or use of cyclopropanes as versatile strategic intermediates.

340 citations

Journal ArticleDOI
TL;DR: The phosphoramide-based bifunctional catalysts achieved better enantiofacial control than the analogous H-bond-donor-derived catalysts in these reactions, suggesting the potential of the former in new chiral catalyst development.
Abstract: Conspectus3,3-Disubstituted oxindoles are widely distributed in natural products, drugs, and pharmaceutically active compounds. The absolute configuration and the substituents on the fully substituted C3 stereocenter of the oxindole often significantly influence the biological activity. Therefore, tremendous efforts have made to develop catalytic enantioselective syntheses of this prominent structural motif. Research in this area is further fueled by the ever-increasing demand for modern probe- and drug-discovery programs for synthetic libraries of chiral compounds that are derived from privileged scaffolds with high structural diversity. Notably, the efficient construction of fully substituted C3 stereocenters of oxindole, tetrasubstituted or all-carbon quaternary, spirocyclic or not, also becomes a test ground for new synthetic methodologies.We have been engaged in developing efficient methods for diversity-oriented synthesis of chiral 3,3-disubstituted oxindoles from readily available starting material...

276 citations

Journal ArticleDOI
TL;DR: It is demonstrated that carbon-carbon bonds have the potential to be a general principle in organic synthesis for the regio-, diastereo-, and even enantioselective preparation of adducts despite the fact that C-C single bonds are among the least reactive functional groups.
Abstract: Most of the efforts of organic chemists have been directed to the development of creative strategies to build carbon–carbon and carbon–heteroatom bonds in a predictable and efficient manner. In this Review, we show an alternative approach where challenging molecular skeletons could be prepared through selective cleavage of carbon–carbon bonds. We demonstrate that it has the potential to be a general principle in organic synthesis for the regio-, diastereo-, and even enantioselective preparation of adducts despite the fact that CC single bonds are among the least reactive functional groups. The development of such strategies may have an impact on synthesis design and can ultimately lead to new selective and efficient processes for the utilization of simple hydrocarbons.

250 citations

Journal ArticleDOI
TL;DR: Recent progress in cyclization and annulation reactions initiated by ring-opening of small rings is presented, including the own work using donor-acceptor cyclopropanes and cyclobutanes.

215 citations

References
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Journal ArticleDOI
TL;DR: The pathways of Ethylene Biosynthesis, Regulation in Ripening Fruits and Senescing Flowers and Regulation by Light and Carbon Dioxide are traced.
Abstract: PATHWAY OF ETHYLENE BIOSyNTHESIS 156 Methionine as an Intermediate ....... 157 S-Adenosylmethionine as an Intermediate 158 I-Aminocyclopropanecarboxylic Acid as an Intermediate . ......... 158 Methionine Cycle ........ 161 Conversion of l-Aminocyclopropanecarboxylic Acid to Ethylene 164 REGULATION OF ETHYLENE BIOSYNTHESIS 167 Regulation in Ripening Fruits and Senescing Flowers ...... 167 Auxin-Induced Ethylene Production 169 Regulation of Ethylene Biosynthesis by Ethylene 169 Stress-Induced Ethylene Production . . . . . . . . 171 Regulation by Light and Carbon Dioxide 173 Inhibitors of Ethylene Biosynthesis : 174 Conjugation of l-Aminocyclopropanecarboxylic Acid to l-(Malonylamino) cyclopropanecarboxylic Acid 178 CONCLUDING REMARKS 180

3,261 citations

Journal ArticleDOI
TL;DR: This review will focus mainly on the new methods that have appeared in the literature since 1989 for stereoselective cyclopropanation reactions from olefins: the halomethylmetal-mediated cycloalkane reactions, the transition metal-catalyzed decomposition of diazo compounds, and the nucleophilic addition-ring closure sequence.
Abstract: Organic chemists have always been fascinated by the cyclopropane subunit.1 The smallest cycloalkane is found as a basic structural element in a wide range of naturally occurring compounds.2 Moreover, many cyclopropane-containing unnatural products have been prepared to test the bonding features of this class of highly strained cycloalkanes3 and to study enzyme mechanism or inhibition.4 Cyclopropanes have also been used as versatile synthetic intermediates in the synthesis of more functionalized cycloalkanes5,6 and acyclic compounds.7 In recent years, most of the synthetic efforts have focused on the enantioselective synthesis of cyclopropanes.8 This has remained a challenge ever since it was found that the members of the pyrethroid class of compounds were effective insecticides.9 New and more efficient methods for the preparation of these entities in enantiomerically pure form are still evolving, and this review will focus mainly on the new methods that have appeared in the literature since 1989. It will elaborate on only three types of stereoselective cyclopropanation reactions from olefins: the halomethylmetal-mediated cyclopropanation reactions (eq 1), the transition metal-catalyzed decomposition of diazo compounds (eq 2), and the nucleophilic addition-ring closure sequence (eqs 3 and 4). These three processes will be examined in the context of diastereoand enantiocontrol. In the last section of the review, other methods commonly used to make chiral, nonracemic cyclopropanes will be briefly outlined.

1,426 citations