Addition to Olefins

Commercial phosphine derivatives are produced either by the acid-cataly2ed addition of phosphine to an aldehyde or by free-radical addition to olefins, particulady a-olefins. The reactions usually take place in an autoclave under moderate pressures (<4 MPa (580 psi)) and at temperatures between 60 and 100°C. 

Etherification. Ethers of amyl alcohols have been prepared by reaction with ben2hydrol (63), activated aromatic haUdes (64), dehydration-addition reactions (65), addition to olefins (66—71), alkoxylation with olefin oxides (72,73) and displacement reactions involving thek alkah metal salts (74—76). 

Addition to Olefins. OrganohydrosHanes can also be prepared by addition of halosHanes and organosilanes containing multiple Si—H bonds to olefins. These reactions are catalyzed by platinum, platinum salts, peroxides, ultraviolet light, or ionizing radiation. 

Sulfur dichloride undergoes many of the same reactions with organic compounds as described for sulfur monochloride. Addition to olefins affords a route to bis(2-chloroalkyl) sulfides and, ia certain cases, heterocycHc sulfides (159,160). 

In dihalocarbene generation by phase-transfer catalysis the following steps seem to be involved (15) formation of CX anions dynamically anchored at the boundary reversible detachment with the help of the catalyst reversible carbene formation [Q+ CX3 ] [Q + X ] + CX2 addition to olefin. 

Gyanamides and Derivatives A/-Chloro-/-alkylcyanamides, RN(C1)CN, are oils that have medicinal and other appHcations (99). Primary and secondary alkyl-A/-chlorocyanamides add photochemically to olefins yielding 1 1 adducts. By contrast, A/-chloro-A/-/-butylcyanamide initially rearranges photochemically to A/-chloro-Af-/-butylcarbodiimide, (CH2)3CN=C=NC1, prior to addition to olefins giving carbodiimides (67,100). 

Characteristic reactions of singlet oxygen lead to 1,2-dioxetane (addition to olefins), hydroperoxides (reaction with aHyhc hydrogen atom), and endoperoxides (Diels-Alder "4 -H 2" cycloaddition). Many specific examples of these spectrally sensitized reactions are found iu reviews (45—48), earlier texts (15), and elsewhere iu the Engchpedia. 

The acylation of enamines derived from cyclic ketones, which can lead to the acyl ketone or ring expansion (692-694), was studied by NMR and mass spectroscopic analysis of the products (695,696). In a comparative study of the rates of diphenylketene addition to olefins, a pronounced activation was observed in enamines (697). Enamine N- and C-acylation products were obtained from reactions of Schiff s bases (698), vinylogous urethanes (699), cyanamides (699), amides (670,700), and 2-benzylidene-3-methylbenzothiazoline (672) with acid chlorides, anhydrides, and dithio-esters (699). 

These singlet and triplet state species exhibit the important differences in chemical behavior to be expected. The former species, with their analogy to carbonium ions, are powerful electrophiles and the relative rates of their reaction with a series of substrates increases with the availability of electrons at the reaction center their addition reactions with olefins are stereospecific. Triplet state species are expected to show the characteristics of radicals i.e., the relative rates of additions to olefins do not follow the same pattern as those of electrophilic species and the additions are not stereospecific. 

Formation of C-C Bonds by Addition to Olefinic Double Bonds Enimines, Nitroalkenes, 4,5-Dihydrooxazoles, a,/MJnsaturated Sulfones, Sulfoxides and Sulfoximines... 

For a long time, this finding was correlated with the observation that substituents at a radical center tend to enhance its stability (Section 1.1.2). This in turn led to the belief that the degree of stabilization conferred on the product radical by the substituents was the prime factor determining the orientation and rate of radical addition to olefins. That steric, polar, or other factors might favor the same outcome was either considered to be of secondary importance or simply ignored. ... 

Phenyl diazomethyl sulphoxide 583 formed in situ from diazomethane and benzenesul-phinyl chloride undergoes addition to olefins affording the corresponding cyclopropyl... 

The primary attack of an electrophile takes place during both the electrophilic addition to olefines and the cationic polymerization resulting in the formation of a car-benium ion R—C+H—CH3 as a reactive intermediate from the olefine or monomer R—CH=CH2 72) (Eq. 16). In the simplest of cases, the electrophile is a proton. 

Phosphine itself as well as primary and secondary phosphines undergo metal-catalyzed additions to olefins and formaldehyde. More than 40 years ago, some Ger-... 

Deubel, D. V., Frenking, G., 1999, Are there Metal Oxides that Prefer a [2+2] Addition over a [3+2] Addition to Olefins Theoretical Study of the Reaction Mechanism of LRe03 Addition (L = O", Cl, Cp) to Ethylene , 7. Am. 

It is of interest to investigate the usefulness of this theory to the chemical change involving the interaction between the conjugated systems 56,62,145). Such a-n interactions are frequently stereoselective. The addition to olefinic double bonds and the a, -elimination are liable to take place with the fraMS-mode 146h The Diels-Alder reaction occurs with the cis-fashion with respect to both diene and dienophile. 

IV-Nitrosoamines undergo addition to olefins upon photolysis in the presence of acid to produce a-r-aminonitrosoalkanes in which the amine moiety adds to the less substituted carbon of the double bond<96) ... 

Isoprene and piperylene undergo photochemical cross-addition to olefins to yield products similar to those observed for butadiene<27) ... 

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