Cyclopropanes

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Cyclopropanes are a family of organic compounds containing the cyclopropyl group. The parent is cyclopropane (C3H6).

Contents

Synthesis and reactions

Most cyclopropanes are not prepared from the parent cyclopropane, which is somewhat inert. Cyclopropyl groups are often prepared by cyclization of 1,3-difunctional alkanes. An example of the former, cyclopropyl cyanide is prepared by the reaction of 4-chlorobutyronitrile with a strong base. [1] Phenylcyclopropane is produced analogously from the 1,3-dibromide. [2]

A second major route to cyclopropanes entails addition of methylene (or its substituted derivatives) to an alkene, a process called cyclopropanation. [3]

Substituted cyclopropanes undergo the reactions associated with the cyclopropyl ring or the substituents. Vinylcyclopropanes are a special case as they undergo vinylcyclopropane rearrangement.

Applications and occurrence

(1R,3R)- or (+)-trans-chrysanthemic acid. (R,R)-(+)-trans-chrysanthemic acid.svg
(1R,3R)- or (+)-trans-chrysanthemic acid.

Cyclopropane derivatives are numerous. [4] Many biomolecules and pharmaceutical drugs feature the cyclopropane ring. Famous example is aminocyclopropane carboxylic acid, which is the precursor to ethylene, a plant hormone. [5]

The pyrethroids are the basis of many insecticides. [6] Several cyclopropane fatty acids are known.

1-Aminocyclopropane-1-carboxylic acid plays an important role in the biosynthesis of the plant hormone ethylene. 1-aminocyclopropanecarboxylic acid 200.svg
1-Aminocyclopropane-1-carboxylic acid plays an important role in the biosynthesis of the plant hormone ethylene.

Cyclopropane derivatives are numerous. [7] Many biomolecules and pharmaceutical drugs feature the cyclopropane ring. Famous example is aminocyclopropane carboxylic acid, which is the precursor to ethylene, a plant hormone.

Related Research Articles

A diol is a chemical compound containing two hydroxyl groups. An aliphatic diol is also called a glycol. This pairing of functional groups is pervasive, and many subcategories have been identified.

<span class="mw-page-title-main">Acyl halide</span> Oxoacid compound with an –OH group replaced by a halogen

In organic chemistry, an acyl halide is a chemical compound derived from an oxoacid by replacing a hydroxyl group with a halide group.

The Simmons–Smith reaction is an organic cheletropic reaction involving an organozinc carbenoid that reacts with an alkene to form a cyclopropane. It is named after Howard Ensign Simmons, Jr. and Ronald D. Smith. It uses a methylene free radical intermediate that is delivered to both carbons of the alkene simultaneously, therefore the configuration of the double bond is preserved in the product and the reaction is stereospecific.

<span class="mw-page-title-main">Peroxy acid</span> Organic acid having a peroxide bond

A peroxy acid is an acid which contains an acidic –OOH group. The two main classes are those derived from conventional mineral acids, especially sulfuric acid, and the peroxy derivatives of organic carboxylic acids. They are generally strong oxidizers.

<span class="mw-page-title-main">Glutaric acid</span> Chemical compound

Glutaric acid is the organic compound with the formula C3H6(COOH)2. Although the related "linear" dicarboxylic acids adipic and succinic acids are water-soluble only to a few percent at room temperature, the water-solubility of glutaric acid is over 50% (w/w).

<span class="mw-page-title-main">Cyclopentene</span> Organic compound; 5-sided hydrocarbon ring

Cyclopentene is a chemical compound with the formula (CH2)3(CH)2. It is a colorless liquid with a petrol-like odor. It has few applications, and thus is mainly used as a minor component of gasoline, present in concentrations of less than 1%. It is one of the principal cycloalkenes.

Cyclobutene is an organic compound with the chemical formula C4H6. It is a cycloalkene. It is a colorless gas that easily condenses. It is of interest in research but currently has no practical applications. A modern synthesis involves the 2-step dehydration of cyclobutanol. The compound was first prepared by thermolysis of the ammonium salt [C4H7N(CH3)3]OH.

In organic chemistry, cyanocarbons are a group of chemical compounds that contain several cyanide functional groups. Such substances generally are classified as organic compounds, since they are formally derived from hydrocarbons by replacing one or more hydrogen atoms with a cyanide group. One of the simplest member is C(CN)4. Organic chemists often refer to cyanides as nitriles.

<span class="mw-page-title-main">1,4-Benzoquinone</span> Chemical compound

1,4-Benzoquinone, commonly known as para-quinone, is a chemical compound with the formula C6H4O2. In a pure state, it forms bright-yellow crystals with a characteristic irritating odor, resembling that of chlorine, bleach, and hot plastic or formaldehyde. This six-membered ring compound is the oxidized derivative of 1,4-hydroquinone. The molecule is multifunctional: it exhibits properties of a ketone, being able to form oximes; an oxidant, forming the dihydroxy derivative; and an alkene, undergoing addition reactions, especially those typical for α,β-unsaturated ketones. 1,4-Benzoquinone is sensitive toward both strong mineral acids and alkali, which cause condensation and decomposition of the compound.

<span class="mw-page-title-main">Ring expansion and contraction</span> Chemical phenomenon within ring systems

Ring expansion and ring contraction reactions expand or contract rings, usually in organic chemistry. The term usually refers to reactions involve making and breaking C-C bonds, Diverse mechanisms lead to these kinds of reactions.

α-Halo ketone

In organic chemistry, an α-halo ketone is a functional group consisting of a ketone group or more generally a carbonyl group with an α-halogen substituent. α-Halo ketones are alkylating agents. Prominent α-halo ketones include phenacyl bromide and chloroacetone.

<span class="mw-page-title-main">Cyclopropanation</span> Chemical process which generates cyclopropane rings

In organic chemistry, cyclopropanation refers to any chemical process which generates cyclopropane rings. It is an important process in modern chemistry as many useful compounds bear this motif; for example pyrethroid insecticides and a number of quinolone antibiotics. However, the high ring strain present in cyclopropanes makes them challenging to produce and generally requires the use of highly reactive species, such as carbenes, ylids and carbanions. Many of the reactions proceed in a cheletropic manner.

The Kulinkovich reaction describes the organic synthesis of substituted cyclopropanols through reaction of esters with dialkyl­dialkoxy­titanium reagents, which are generated in situ from Grignard reagents containing a hydrogen in beta-position and titanium(IV) alkoxides such as titanium isopropoxide. This reaction was first reported by Oleg Kulinkovich and coworkers in 1989.

<span class="mw-page-title-main">Cyclopropanone</span> Chemical compound

Cyclopropanone is an organic compound with molecular formula (CH2)2CO consisting of a cyclopropane carbon framework with a ketone functional group. The parent compound is labile, being highly sensitive toward even weak nucleophiles. Surrogates of cyclopropanone include the ketals.

<span class="mw-page-title-main">Benzyl cyanide</span> Chemical compound

Benzyl cyanide (abbreviated BnCN) is an organic compound with the chemical formula C6H5CH2CN. This colorless oily aromatic liquid is an important precursor to numerous compounds in organic chemistry.

Silylation is the introduction of one or more (usually) substituted silyl groups (R3Si) to a molecule. Silylations are core methods for production of organosilicon chemistry. Silanization involves similar methods but usually refers to attachment of silyl groups to solids.

The Buchner ring expansion is a two-step organic C-C bond forming reaction used to access 7-membered rings. The first step involves formation of a carbene from ethyl diazoacetate, which cyclopropanates an aromatic ring. The ring expansion occurs in the second step, with an electrocyclic reaction opening the cyclopropane ring to form the 7-membered ring.

<span class="mw-page-title-main">Cyclopropyl cyanide</span> Chemical compound

Cyclopropyl cyanide is an organic compound consisting of a nitrile group as a substituent on a cyclopropane ring. It is the smallest cyclic compound containing a nitrile.

α,β-Unsaturated carbonyl compound Functional group of organic compounds

α,β-Unsaturated carbonyl compounds are organic compounds with the general structure (O=CR)−Cα=Cβ-R. Such compounds include enones and enals, but also carboxylic acids and the corresponding esters and amides. In these compounds the carbonyl group is conjugated with an alkene. Unlike the case for carbonyls without a flanking alkene group, α,β-unsaturated carbonyl compounds are susceptible to attack by nucleophiles at the β-carbon. This pattern of reactivity is called vinylogous. Examples of unsaturated carbonyls are acrolein (propenal), mesityl oxide, acrylic acid, and maleic acid. Unsaturated carbonyls can be prepared in the laboratory in an aldol reaction and in the Perkin reaction.

4-Chlorobutyronitrile is the organic compound with the formula ClCH2CH2CH2CN. With both chloro and cyano functional groups, it is a bifunctional molecule. It is a colorless liquid.

References

  1. Schlatter, M. J. (1943). "Cyclopropyl Cyanide". Organic Syntheses. 23: 20. doi:10.15227/orgsyn.023.0020.
  2. "Cyclopropylbenzene". Organic Syntheses. 44: 30. 1964. doi:10.15227/orgsyn.044.0030.
  3. Maruoka, Keiji; Sakane, Soichi; Yamamoto, Hisashi (1989). "Selective Cyclopropanation of (S)-(−)-Perillyl Alcohol: 1-Hydroxymethyl-4-(1-Methylcyclopropyl)-1-Cyclohexene". Organic Syntheses. 67: 176. doi:10.15227/orgsyn.067.0176.
  4. Rappoport, Zvi, ed. (1995). The Chemistry of the Cyclopropyl Group. The Chemistry of Functional Groups. Vol. 2. doi:10.1002/0470023481. ISBN   0471940747.
  5. 1 2 Kieber, Joseph J.; Schaller, G. Eric (2019-07-01). "Behind the Screen: How a Simple Seedling Response Helped Unravel Ethylene Signaling in Plants". The Plant Cell. 31 (7): 1402–1403. doi:10.1105/tpc.19.00342. ISSN   1040-4651. PMC   6635871 . PMID   31068448.
  6. Faust, Rüdiger (2001). "Fascinating Natural and Artificial Cyclopropane Architectures". Angewandte Chemie International Edition. 40 (12): 2251–2253. doi:10.1002/1521-3773(20010618)40:12<2251::AID-ANIE2251>3.0.CO;2-R. PMID   11433485.
  7. Rappoport, Zvi, ed. (1995). The Chemistry of the Cyclopropyl Group. The Chemistry of Functional Groups. Vol. 2. doi:10.1002/0470023481. ISBN   0471940747.