Acyclic double

Diethyl ether. Either on photolysis or on standing in concentrated solution dimers are obtained (dimerization possibly at the acyclic double bond). ... 

In this synthesis the geometry of the acyclic double bonds is controlled through their formation as part of the thiane ring. Thiacyclohexanone (711) was converted to 4-thia-l-methylcyclohexene by reaction with methylmagnesium iodide and subsequent dehydration. Metallation of (712) with s-butyllithium and alkylation of the anion with the epoxide (713) gave a tertiary alcohol which was dehydrated to yield (714). A second alkylation of (714) with trails-4-chloro-3-methyl-2-butene 1-oxide (715) completed the carbon skeleton of the Cis juvenile hormone. Reduction of (716) with lithium in ethylamine and then desulfurization with Raney nickel led to trienol (717), a product converted previously to (718). 

Benzene may also be interrelated with the simplest acyclic double bond-containing organic compound, ethylene, as well as with (Z)- and ( )-2-butene,... 

Yang and Burton studied reductive radical additions of iododifluoroacetate 37 to olefins 38 and dienes catalyzed by 6-17 mol% of a catalyst generated from NiCl2 and stoichiometric amounts of zinc in the presence of water (Fig. 8) [90, 91]. Olefins gave the reductive addition products 40a in 60-83% yield, while 1,5-hexadiene or 1,8-nonadiene provided double addition products exclusively in 55% and 73% yield. 1,7-Hexadiene gave an inseparable mixture of the expected acyclic double addition product and a tandem addition/cyclization product, in which the former dominated. The radical nature of the addition is supported by inhibition of the reaction by para-dinitrobenzene. The reaction proceeds probably via initially formed atom transfer product 39, which is subsequently reduced by nickel(0) and zinc. This is supported by deuterium incorporation, when D20 was used instead of water. No deuterium incorporation was observed with THF-dg, thus ruling out hydrogen transfer from the solvent. 

The Food Chemicals Codex, Fifth Edition, uses the nomenclature convention (Z) and (E) to specify the structure of acyclic double bonds in organic chemicals, specifically cis and trans. The FCC name of the substance is followed, where available, by the number assigned to the substance by the Flavor and Extract Manufacturers Association (FEMA) and by its synonym(s). The explanatory notes to the specifications in this section apply throughout the tabular series and are as follows ... 

The last example shows that selective hydroboration of an acyclic double bond in the presence of a cyclic double bond can be achieved. 

Several bacterial species produce C45 and C50 carotenoids which contain one or two extra isoprenyl groups. Although their biosynthesis has not been studied, it is probable that instead of proton-initiated cyclisation at the polyene termini, attack by dimethyl allyl pyrophosphate results in substances such as the symmetrical decaprenoxanthin (P439) (68). The stereochemistry of the isolated acyclic double bond was shown to be trans by the n.m.r. spectrum of the corresponding aldehyde. Other carotenoids present in Flavobacterium... 

For example, the addition of acrolein to myrcene gives a product known by trade names such as Myrac Aldehyde or Empetal . The product is a mixture of isomers because the dienophile can line up in two orientations relative to the diene. For simplicity, only the major isomer, in which the two substituents on the cyclohexane ring are 1,4 relative to each other, is shown. Hydration of the acyclic double bond of Empetal gives a hydroxy-aldehyde, known as Hydroxy empetal or Lyral . Lyral possesses a fine odour reminiscent of the delicate odour of the flowers of lily of the valley and is widely used in perfumery. 

Acyclic monoterpenes geraniol in essential oils, perfume products and luxury foods, production from other terpene products, e.g. beta-pinene acyclic, double unsaturated alcohol, several possible reactions, occurrence as esters, typicjd rose odor... 

As a nonconjugated diene, dicyclopentadiene forms first a monomeric rT.-ir-complex, which is attacked by nucleophiles at the norbomene double bond giving the 6-bonded dimeric complex, jjjg diene has an acyclic double bond this is also preferentially... 

Influence of Polar Functional Groups and Acyclic Double Bond on Polymerization. The polymerization can be carried out in aprotic polar solvents such as ether, tetrahydrofuran, ethyl acetate, acetonitrile and di-methylformamide as well as in hydrocarbons and haloge-nated hydrocarbons. Alcohols, ketones and sulfoxides strongly inhibited the reaction. 

Oxetans.—It has been known for many years that the electronically excited states of carbonyl compounds will add to double bonds to form oxetans. The majority of examples of the Paterno-Buchi reaction, as it is known, involve addition of a carbonyl triplet state to a tt-system, most commonly an isolated double bond. It is accepted that an intermediate in this reaction is a 1,4-biradical with a lifetime long enough to destroy the stereochemical integrity of an acyclic double bond. Intramolecular reactions are of synthetic value since in many cases they proceed regiospecifically. For example, 3-ent/o-acylbicyclo[3.3.1]non-6-enes give exclusively 2,4-oxo-bridged protoadamantanes upon excitation... 

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