Alkenes structures

The products formed by oxidative deavage of an alkene depend on the alkene structure and the agent used Acid fluorides are formed by ozonization of per-fluoroalkenes in tnfluoroacetic acid [3t5] (equation 28)... 

Thomson NOW Click Organic Interactive to use a web-based palette to draw alkene structures based on their IUPAC names. 

Fig. 43 Tin-119 spectrum of a 1,1-distannyl-l-alkene (structure shown). Signals result from various isotopomers 1 from molecules containing one tin-119 nucleus, 2 from molecules containing one tin-119 and one tin-117 nucleus, 3 from molecules containing two tin-119 nuclei and 4 from molecules containing tin-119 and carbon-13 nuclei...

Epoxidation of various alkenes over TS-2 influence of alkene structure... 

Oxidation of unsaturated alcohols in the presence ofTS-1 effect of alkene structure on selectivity... 

As shown in equation 90, the ionic intermediate can follow several reaction routes. The product distribution is therefore controlled not only by the nature of the intermediate, whether bridged or weakly bridged, but also by association with its nucleophilic partner and by the rate ratios derived from the different reaction paths. All these factors depend on the alkene structure, the electrophile and the reaction conditions (solvent, added salts, temperature). 

The alkene structure and the solvent polarity markedly affect the reaction rate. However, these effects are not easy to rationalize since, as shown in equation 90, one or more intermediates may be involved and each factor can influence the individual rate constants in a different way. It follows that only when the first step is rate determining can the observed rate constant k0bsd t>e interpreted straightforwardly. 

Structure effects on the rate of selective or total oxidation of saturated and unsaturated hydrocarbons and their correlations have been used successfully in the exploration of the reaction mechanisms. Adams 150) has shown that the oxidation of alkenes to aldehydes or alkadienes on a BijOj-MoOj catalyst exhibits the same influence of alkene structure on rate as the attack by methyl radicals an excellent Type B correlation has been gained between the rate of these two processes for various alkenes (series 135, five reactants, positive slope). It was concluded on this basis that the rate-determining step of the oxidation is the abstraction of the allylic hydrogen. Similarly, Uchi-jima, Ishida, Uemitsu, and Yoneda 151) correlated the rate of the total oxidation of alkenes on NiO with the quantum-chemical index of delo-calizability of allylic hydrogens (series 136, five reactants). 

Mechanistic studies have been most thorough with the sulfenyl halides.63 The reactions show moderate sensitivity to alkene structure, with electron-releasing groups on the alkene accelerating the reaction. The addition can occur in either the Markownikoff or anti-Markownikoff sense.64 The variation in regioselectivity can be understood by... 

When alkenes react with concentrated sulfuric acid, the corresponding sulfate esters (alkyl hydrogen sulfate, dialkyl sulfate) are formed. Depending on the alkene structure and the acid concentration, ester formation is accompanied by polymer formation (see Section 13.1.1). Hydrolysis of the sulfate esters allows the synthesis of alcohols. The reaction, called indirect hydration, is applied in the manufacture of ethanol and 2-propanol (see Section 6.1.3). 

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