Allylic compounds Lithium-Ethylamine

Otherwise, reduction of allylic dithiocaitiamates proved regio- and stereo-selective when carried out with lithium in ethylamine (Scheme 32), but leads to a mixture of alkenic compounds when carried out with Raney nickel. 

The previously unknown (+ )-(lS,2S,4R)-isodihydrocarveol (157) has been made from (+ )-limonene epoxide (158) as a component of a mixture of isomers, either with lithium in ethylamine or with the stoicheiometric amount of lithium aluminium hydride. Dihydrocarveol (159) has been synthesized from 4-acetyl-1-methylcyclohexene by conventional means.A method that is said to convert allyl alcohols into the corresponding chlorides without allyl rearrangement has been applied to carveol. The chloride was indeed obtained, but since the rotations of the compounds were not recorded it is unfortunately impossible to draw any conclusions about rearrangement. An ingenious synthesis of pure stereoisomers of carvomenthone-9-carboxylic acids involves a [2 -I- 2]-type cycloaddition of an ynamine to 2-methylcyclohex-5-enone (160). This leads... 

The allylic alcohol of 9 was converted to the chloride 10 and coupled with the thioether anion of previously synthesized triene 11 (Scheme 2). The compound 12 now has all 30 carbons, and five double bonds, of squalene epoxide. Reduction with lithium in ethylamine removed the thioether activating group... 

Lithium in ethylamine at -78 °C selectively cleaves the allylic ether linkage of 5,6-dihydro-2i/-pyrans with reduction to furnish Z-homoallylic alcohols 2,5-dihydrofurans give Z-allylic alcohols. The method was used in a novel synthesis of Z-hex-3-enol, leaf alcohol (51), which is also an important compound in the perfume industry. ... 

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