Allyl alcohol exposure

A valuable feature of the Nin/Crn-mediated Nozaki-Takai-Hiyama-Kishi coupling of vinyl iodides and aldehydes is that the stereochemistry of the vinyl iodide partner is reflected in the allylic alcohol coupling product, at least when disubstituted or trans tri-substituted vinyl iodides are employed.68 It is, therefore, imperative that the trans vinyl iodide stereochemistry in 159 be rigorously defined. Of the various ways in which this objective could be achieved, a regioselective syn addition of the Zr-H bond of Schwartz s reagent (Cp2ZrHCl) to the alkyne function in 165, followed by exposure of the resulting vinylzirconium species to iodine, seemed to constitute a distinctly direct solution to this important problem. Alkyne 165 could conceivably be derived in short order from compound 166, the projected product of an asymmetric crotylboration of achiral aldehyde 168. 

We had two possible routes in which alcohol 72 could be used (Scheme 8.19). Route A would involve rearrangement of tertiary alcohol 72 to enone 76. Deprotonation at C5 and generation of the enolate followed by exposure to an oxaziridine or other oxygen electrophile equivalents might directly afford the hydrated furan C-ring of phomactin A (see 82) via hydroxy enone 81. We had also hoped to make use of a chromium-mediated oxidative rearrangement of tertiary allylic alcohols. Unfortunately, treatment of 72 to PCC produced only unidentified baseline materials, thereby quickly eliminating this route. 

The very first example of the catalytic reductive cyclization of an acetylenic aldehyde involves the use of a late transition metal catalyst. Exposure of alkynal 78a to a catalytic amount of Rh2Co2(CO)12 in the presence of Et3SiH induces highly stereoselective hydrosilylation-cyclization to provide the allylic alcohol 78b.1 8 This rhodium-based catalytic system is applicable to the cyclization of terminal alkynes to form five-membered rings, thus complementing the scope of the titanocene-catalyzed reaction (Scheme 54). 

The similarity between the measured activation energies for the reaction-limited production of acrolein over Cu20(100) from allyl alcohol in UHV or propene following a 1 atm. exposure gives a clear indication that these reactions involve the same surface intermediate, an allyloxy. This similarity also suggests that the surface intermediates formed by these two routes behave in a chemically similar fashion. For the (100) surface, the Cu -alkoxide surface complex is similar regardless of whether oxygen from... 

Figure 5. Comparison of acrolein desorption traces from the Cu2O(100) surface following (a) exposure to propene at 1 atm., (b) allyl alcohol adsorption in UHV and (c) acrolein adsorption in UHV.

Bromination of the enol ether product with two equivalents of bromine followed by dehydrobromination afforded the Z-bromoenol ether (Eq. 79) which could be converted to the zinc reagent and cross-coupled with aryl halides [242]. Dehydrobromination in the presence of thiophenol followed by bromination/dehydrobromination affords an enol thioether [243]. Oxidation to the sulfone, followed by exposure to triethylamine in ether, resulted in dehydrobromination to the unstable alkynyl sulfone which could be trapped with dienes in situ. Alternatively, dehydrobromination of the sulfide in the presence of allylic alcohols results in the formation of allyl vinyl ethers which undergo Claisen rearrangements [244]. Further oxidation followed by sulfoxide elimination results in highly unsaturated trifluoromethyl ketonic products (Eq. 80). 

In a different sequence of reactions, N-acetylation of 274 and exposure of the intermediate imide 275 to ethanolic KOH gave a mixture (about 2 1) of the desired carboxylic acid 276 together with the starting lactam 274 via the non-selective hydrolysis of the imide moiety of 275 (148a,c). When 276 was treated with /V-bromosuccinimide (NBS), an intermediate bromolactone was produced which was heated at reflux in pyridine in the presence of DBU to give 277. The conversion of the lactone 277 to the lactam 278 was effected by heating 277 in aqueous NaOH followed by protection of the resulting allylic alcohol function as a tetrahydropyranyl ether. 

Toxicity Exposure to vapors of allyl alcohol causes irritation to the eyes, skin, and upper respiratory tract. Laboratory studies with animals have shown symptoms of local muscle spasms, pulmonary edema, tissue damage to liver and kidney, convulsions, and death. In view of this, workers should be instructed to wear protective clothing.2 105 106... 

Figure 3. HREEL spectra observed after exposure of 2.2 L propanal, 2.6 L acrolein, 1.3 L allyl alcohol, or 2.3 L 1-propanol to the clean Rh(l 11) surface and annealing to 301 K, 247 K, 304 K, and 258 K, respectively, to complete the decarbonylation reaction.

The addition of a-lithiovinyltrimethylsilane 151 83), generated from a-bromovinyl-trimethylsilane84,) with r-BuLi (1.5 equivalents) at —78 °C in ether, to ketones and aldehydes was also investigated. The allylic alcohols 152 thus obtained underwent smooth cyclopropanation when the modified Simmons-Smith procedure utilizing EtZnI85) was applied. The cyclopropylcarbinols 153 were directly dehydrated without rearrangement upon exposure to catalytic amounts of p-TsOH in benzene at 20 °C to give 149 in yields of 52-75%, Eq. (48) 79,8L). 

By the exposure of an allylic alcohol to an amide acetal, a y,<5-unsaturated amide is obtained. For example, 9787 and 9988 are produced from 95 and corresponding alcohols (equations 19 and 20). 

Use and exposure Allyl alcohol is used in the manufacture of allyl esters as monomers and prepolymers for the manufacture of resins and plastics. It has a large use in the preparation of pharmaceutical products, in organic synthesis, and as a fungicide and herbicide. Workers engaged in industries such as the manufacture of drugs, pesticides, allyl esters, organic chemicals, resins, war gas, and plasticizers are often exposed to this alcohol. - ... 

A related oxidative rearrangement of cephem dioxides has been reported in which an alkene is oxidized stereospecifically with rearrangement to the allylic alcohol in good yield by simple exposure to a palladium/caibon catalyst, as depicted in equation (12). Adventitious oxygen preadsotbed on the catalyst seems the likely oxida The reaction fails on the parent ccphem or its monoxide, or on the free acid of the dioxide. This reaction would seem to hold some promise for furdier utility in the cephem field and odier related systems. 

Acute exposure to allyl alcohol causes liver and kidney damage. Allyl alcohol is classified as a periportal hepatotoxicant since it selectively damages the periportal region of the liver. Studies have shown that in adult rats, allyl alcohol produces a moderate to marked periportal necrosis with attendant inflammation, hemorrhage, and also decreases hepatic cytochrome P-450, benzphentamine N-demethyla-tion, and ethoxyresorufin 0-deethylation activities by 30%. In immature rats, it lowered both cytochrome P-450 activity (30%) and ethoxyresorufin O-deethylation (75%). Benzphetamine N-demethyl-ation was not significantly affected in immature rats. Intraperitoneal administration of 1.5 mmol kg of allyl alcohol to starved Swiss albino mice causes the development of hemolysis in 50% of the animals. Other toxic effects include renal necrosis, pulmonary edema, and central nervous system effects at higher dose levels. 

The most important adverse effects of occupational exposure to allyl alcohol are upper respiratory tract irritation and burning of the eyes. The substance may cause effects on the muscles, resulting in local spasm and aching. The appearance of these effects may be delayed after exposure. 

Chronic exposure to allyl alcohol can cause liver and kidney damage. 

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