Cubane is a synthetic hydrocarbon compound with the formula C8H8. It consists of eight carbon atoms arranged at the corners of a cube, with one hydrogen atom attached to each carbon atom. A solid crystalline substance, cubane is one of the Platonic hydrocarbons and a member of the prismanes. It was first synthesized in 1964 by Philip Eaton and Thomas Cole. Before this work, Eaton believed that cubane would be impossible to synthesize due to the "required 90 degree bond angles". The cubic shape requires the carbon atoms to adopt an unusually sharp 90° bonding angle, which would be highly strained as compared to the 109.45° angle of a tetrahedral carbon. Once formed, cubane is quite kinetically stable, due to a lack of readily available decomposition paths. It is the simplest hydrocarbon with octahedral symmetry.
In organic chemistry, a nucleophilic addition (AN) reaction is an addition reaction where a chemical compound with an electrophilic double or triple bond reacts with a nucleophile, such that the double or triple bond is broken. Nucleophilic additions differ from electrophilic additions in that the former reactions involve the group to which atoms are added accepting electron pairs, whereas the latter reactions involve the group donating electron pairs.
In organic chemistry, the ene reaction is a chemical reaction between an alkene with an allylic hydrogen and a compound containing a multiple bond, in order to form a new σ-bond with migration of the ene double bond and 1,5 hydrogen shift. The product is a substituted alkene with the double bond shifted to the allylic position.
In chemistry, a nitrene or imene is the nitrogen analogue of a carbene. The nitrogen atom is uncharged and monovalent, so it has only 6 electrons in its valence level—two covalent bonded and four non-bonded electrons. It is therefore considered an electrophile due to the unsatisfied octet. A nitrene is a reactive intermediate and is involved in many chemical reactions. The simplest nitrene, HN, is called imidogen, and that term is sometimes used as a synonym for the nitrene class.
An allylic rearrangement or allylic shift is an organic chemical reaction in which reaction at a center vicinal to a double bond causes the double bond to shift to an adjacent pair of atoms:
The Bamford–Stevens reaction is a chemical reaction whereby treatment of tosylhydrazones with strong base gives alkenes. It is named for the British chemist William Randall Bamford and the Scottish chemist Thomas Stevens Stevens (1900–2000). The usage of aprotic solvents gives predominantly Z-alkenes, while protic solvent gives a mixture of E- and Z-alkenes. As an alkene-generating transformation, the Bamford–Stevens reaction has broad utility in synthetic methodology and complex molecule synthesis.
The Johnson–Corey–Chaykovsky reaction is a chemical reaction used in organic chemistry for the synthesis of epoxides, aziridines, and cyclopropanes. It was discovered in 1961 by A. William Johnson and developed significantly by E. J. Corey and Michael Chaykovsky. The reaction involves addition of a sulfur ylide to a ketone, aldehyde, imine, or enone to produce the corresponding 3-membered ring. The reaction is diastereoselective favoring trans substitution in the product regardless of the initial stereochemistry. The synthesis of epoxides via this method serves as an important retrosynthetic alternative to the traditional epoxidation reactions of olefins.
The Stieglitz rearrangement is a rearrangement reaction in organic chemistry which is named after the American chemist Julius Stieglitz (1867–1937) and was first investigated by him and Paul Nicholas Leech in 1913. It describes the 1,2-rearrangement of trityl amine derivatives to triaryl imines. It is comparable to a Beckmann rearrangement which also involves a substitution at a nitrogen atom through a carbon to nitrogen shift. As an example, triaryl hydroxylamines can undergo a Stieglitz rearrangement by dehydration and the shift of a phenyl group after activation with phosphorus pentachloride to yield the respective triaryl imine, a Schiff base.
Strychnine total synthesis in chemistry describes the total synthesis of the complex biomolecule strychnine. The first reported method by the group of Robert Burns Woodward in 1954 is considered a classic in this research field.
Organosilver chemistry is the study of organometallic compounds containing a carbon to silver chemical bond. The theme is less developed than organocopper chemistry.
An oxaziridine is an organic molecule that features a three-membered heterocycle containing oxygen, nitrogen, and carbon. In their largest application, oxaziridines are intermediates in the industrial production of hydrazine. Oxaziridine derivatives are also used as specialized reagents in organic chemistry for a variety of oxidations, including alpha hydroxylation of enolates, epoxidation and aziridination of olefins, and other heteroatom transfer reactions. Oxaziridines also serve as precursors to nitrones and participate in [3+2] cycloadditions with various heterocumulenes to form substituted five-membered heterocycles. Chiral oxaziridine derivatives effect asymmetric oxygen transfer to prochiral enolates as well as other substrates. Some oxaziridines also have the property of a high barrier to inversion of the nitrogen, allowing for the possibility of chirality at the nitrogen center.
An insertion reaction is a chemical reaction where one chemical entity interposes itself into an existing bond of typically a second chemical entity e.g.:
tert-Butylphosphaacetylene is an organophosphorus compound. Abbreviated t-BuCP, it was the first example of an isolable phosphaalkyne. Prior to its synthesis, the double bond rule had suggested that elements of Period 3 and higher were unable to form double or triple bonds with lighter main group elements because of weak orbital overlap. The synthesis of t-BuCP discredited much of the double bond rule and opened new studies into the formation of unsaturated phosphorus compounds.
Rearrangements, especially those that can participate in cascade reactions, such as the aza-Cope rearrangements, are of high practical as well as conceptual importance in organic chemistry, due to their ability to quickly build structural complexity out of simple starting materials. The aza-Cope rearrangements are examples of heteroatom versions of the Cope rearrangement, which is a [3,3]-sigmatropic rearrangement that shifts single and double bonds between two allylic components. In accordance with the Woodward-Hoffman rules, thermal aza-Cope rearrangements proceed suprafacially. Aza-Cope rearrangements are generally classified by the position of the nitrogen in the molecule :
Trifluoroperacetic acid is an organofluorine compound, the peroxy acid analog of trifluoroacetic acid, with the condensed structural formula CF
3COOOH. It is a strong oxidizing agent for organic oxidation reactions, such as in Baeyer–Villiger oxidations of ketones. It is the most reactive of the organic peroxy acids, allowing it to successfully oxidise relatively unreactive alkenes to epoxides where other peroxy acids are ineffective. It can also oxidise the chalcogens in some functional groups, such as by transforming selenoethers to selones. It is a potentially explosive material and is not commercially available, but it can be quickly prepared as needed. Its use as a laboratory reagent was pioneered and developed by William D. Emmons.
In organophosphorus chemistry, the Pudovik reaction is a method for preparing α-aminomethylphosphonates. Under basic conditions, the phosphorus–hydrogen bond of a dialkylphosphite, (RO)2P(O)H, adds across the carbon–nitrogen double bond of an imine (a hydrophosphonylation reaction). The reaction is closely related to the three-component Kabachnik–Fields reaction, where an amine, phosphite, and an organic carbonyl compound are condensed, which was reported independently by Martin Kabachnik and Ellis Fields in 1952. In the Pudovik reaction, a generic imine, RCH=NR', would react with a phosphorous reagent like diethylphosphite as follows:
The phosphaethynolate anion, also referred to as PCO, is the phosphorus-containing analogue of the cyanate anion with the chemical formula [PCO]− or [OCP]−. The anion has a linear geometry and is commonly isolated as a salt. When used as a ligand, the phosphaethynolate anion is ambidentate in nature meaning it forms complexes by coordinating via either the phosphorus or oxygen atoms. This versatile character of the anion has allowed it to be incorporated into many transition metal and actinide complexes but now the focus of the research around phosphaethynolate has turned to utilising the anion as a synthetic building block to organophosphanes.
Phosphasilenes or silylidenephosphanes are a class of compounds with silicon-phosphorus double bonds. Since the electronegativity of phosphorus (2.1) is higher than that of silicon (1.9), the "Si=P" moiety of phosphasilene is polarized. The degree of polarization can be tuned by altering the coordination numbers of the Si and P centers, or by modifying the electronic properties of the substituents. The phosphasilene Si=P double bond is highly reactive, yet with the choice of proper substituents, it can be stabilized via donor-acceptor interaction or by steric congestion.
A transition metal phosphido complex is a coordination complex containing a phosphido ligand (R2P, where R = H, organic substituent). With two lone pairs on phosphorus, the phosphido anion (R2P−) is comparable to an amido anion (R2N−), except that the M-P distances are longer and the phosphorus atom is more sterically accessible. For these reasons, phosphido is often a bridging ligand. The -PH2 ion or ligand is also called phosphanide or phosphido ligand.
1-Phosphaallenes is are allenes in which the first carbon atom is replaced by phosphorus, resulting in the structure: -P=C=C<.
.