Exploring new reactive species for cyclopropanation

Yang, Z.‐Y.; Lorenz, Jon C.; Shi, Yian

doi:10.1016/s0040-4039(98)01954-6

Cited by 171 publications

(104 citation statements)

References 39 publications

Supporting

Mentioning

101

Contrasting

Unclassified

Order By: Relevance

“…After some optimization, this procedure turned out to be easily scalable to produce 4 on a molar scale. The bromovinyl group in 4 was smoothly cyclopropanated [20] with a 3.3-fold excess of CF 3 COOZnCH 2 I (so-called Shis carbenoid) [21] to afford the key intermediate 5 in excellent yield (92 %). Remarkably, the vinyl bromide 4 could be cyclopropanated with a significantly smaller excess of the reagent mixture than a vinyl chloride as reported by Evans et al [22] An initially attempted Swern oxidation of the 3-(1-bromocyclopropyl)-2-hydroxypropionate (5) failed, as it gave a complex mixture containing, along with various by-products, the target ethyl cyclopropylidenepyruvate 1j (about 50 %, according to an 1 H NMR spectrum of the reaction mixture), but the latter could not be isolated in pure form either by column chromatography (silica gel, Florisil and alumina were tested) or by distillation.…”

Section: Resultsmentioning

confidence: 99%

Cyclopropyl Building Blocks for Organic Synthesis, 139. Ethyl Cyclopropylidenepyruvate as a Novel Multifunctional Cyclopropyl Building Block: Facile Preparation and Basic Reaction Patterns

Bagutski

Meijere

2007

Adv Synth Catal

View full text Add to dashboard Cite

Tin(II) chloride-mediated Barbier-type coupling of ethyl glyoxylate with 2,3-dibromopropene followed by Simmons-Smith cyclopropanation and subsequent Dess-Martin oxidation, afforded ethyl 3-(1-bromocycloprop-1-yl)-2-oxopropionate (5), a stable precursor of ethyl cyclopropylidenepyruvate (1j), in good overall yield (65 %), even on a multi-gram scale. The potentially rich chemistry of this novel cyclopropyl building block was illustrated by some basic transformations such as Michael additions of N-, S-, O-and C-nucleophiles (10-91 % yields), Diels-Alder reactions with cyclopentadiene (65 %) and 2,3-dimethylbuta-1,3-diene (66 %) as well as [4 + 2] cycloadditions across the enone moiety of 1j (hetero-Diels-Alder reactions) with furan and enol ethers (65-79 %), thus opening up a ready access to a wide range of new variously functionalized cyclopropane derivatives.

show abstract

Section: Resultsmentioning

confidence: 99%

Cyclopropyl Building Blocks for Organic Synthesis, 139. Ethyl Cyclopropylidenepyruvate as a Novel Multifunctional Cyclopropyl Building Block: Facile Preparation and Basic Reaction Patterns

Bagutski

Meijere

2007

Adv Synth Catal

View full text Add to dashboard Cite

show abstract

“…In 1998, Shi and coworkers reported that a new class of (iodomethyl)zinc compounds (RXZnCH 2 I), readily obtained by the reaction of RXH (ROH, RCO 2 H) with RZnCH 2 I, can efficiently cyclopropanate olefins. 279 The carbenoid reactivity was found to increase with the acidity of RXH. For example, CF 3 …”

Section: The Simmons-smith Reactionmentioning

confidence: 96%

Zinc: Organometallic ChemistryBased in part on the article Zinc: Organometallic Chemistry by Gerard Parkin which appeared in theEncyclopedia of Inorganic Chemistry, First Edition.

Gr��vy¹

2005

Encyclopedia of Inorganic Chemistry

View full text Add to dashboard Cite

Since the discovery of the first organozinc compounds by Sir Edward Frankland in 1849, the organometallic chemistry of zinc made remarkable advances and organozinc species have become essential tools for organic chemists. During the past decade, numerous new and modified procedures for the preparation of the title compounds have been published, rendering their synthesis easier, faster, and less expensive and giving higher yields. The coordination chemistry of organozinc derivatives has been subject of further interest and various intra‐ and intermolecular complexes with different donor ligands have been structurally characterized by X‐ray crystallography and spectroscopic methods. The accumulation of molecular structures, physicochemical studies, and computational calculations has led to a better understanding of the organozinc chemistry, and consequently to the design of new derivatives for specific applications. Even if the development of areas like the chemistry of organozinc anions and cations is still in its early stage, these compounds, which exhibit properties different than those of the parent organometallic species, appear to have promising applications in synthesis and catalytic reactions. During the past ten years, the chemistry of organo‐ gem ‐dizincio derivatives has also been the subject of much interest and progress. These reagents can form two carbon–carbon bonds in a one‐pot reaction and with high stereoselectivity. They became key reagents for organic chemists who want to combine multiple transformations in one operation. The importance of organometallic compounds of zinc can be seen in the growing number of their applications in synthesis. They are used in many reactions such as substitutions, additions to carbonyl compounds and unsaturated systems, cyclopropanations, and polymerizations. Furthermore, as a result of their low reactivity, they tolerate a wide variety of functionalities and perform most of the transformations with high regio‐ and enantioselectivity. After spending more than half a century in the shade of Grignard and organolithium reagents, organozinc reagents are becoming more and more important in modern chemistry.

show abstract

“…Rather than explore this possibility, we devised a shorter route that intercepted an earlier common intermediate, namely enol ether 28. Cyclopropanation of 28 under conditions developed by Shi et al [15] produced cyclopropane 31 in good yield as an inconsequential mixture of stereoisomers. Heating of 31 in a 1:1 mixture of concentrated HCl and methanol at reflux led to smooth formation of (À)-cyclogalgravin (4) in 73 % yield, presumably via an intermediate aldehyde (or the related methyl oxocarbenium ion), which underwent cyclization and elimination.…”

Section: Entry 4)mentioning

confidence: 99%

Stereocontrolled Syntheses of Tetralone‐ and Naphthyl‐Type Lignans by a One‐Pot Oxidative [3,3] Rearrangement/Friedel–Crafts Arylation

Reddel¹,

Lutz²,

Diagne³

et al. 2013

Angewandte Chemie

View full text Add to dashboard Cite

show abstract

Exploring new reactive species for cyclopropanation

Cited by 171 publications

References 39 publications

Cyclopropyl Building Blocks for Organic Synthesis, 139. Ethyl Cyclopropylidenepyruvate as a Novel Multifunctional Cyclopropyl Building Block: Facile Preparation and Basic Reaction Patterns

Cyclopropyl Building Blocks for Organic Synthesis, 139. Ethyl Cyclopropylidenepyruvate as a Novel Multifunctional Cyclopropyl Building Block: Facile Preparation and Basic Reaction Patterns

Zinc: Organometallic ChemistryBased in part on the article Zinc: Organometallic Chemistry by Gerard Parkin which appeared in theEncyclopedia of Inorganic Chemistry, First Edition.

Stereocontrolled Syntheses of Tetralone‐ and Naphthyl‐Type Lignans by a One‐Pot Oxidative [3,3] Rearrangement/Friedel–Crafts Arylation

Contact Info

Product

Resources

About