3-Hydroxy-2,4-dienals

Prominent volatiles related to "grassy" flavor of lamb according to Suzuki (34) were hexanal, heptanal, 2,3-octanedione, 2,4-hepta-dienal, 3-hydroxy-2-octanone, 2-nonenal, 2-decenal, 2,4-decadienal,... 

It was pointed out that the ylide 20 can be regarded as a j5-formylvinyl anion equivalent 21 it reacts with aldehydes to give oxiranes, which can readily be converted under mild conditions into 4-hydroxy-2-( )-enals (equation 7). A vinylogue of 20 has been converted in the same way into a 6-hydroxy-2, 4-( , F)-dienal this reaction enables a five carbon atom homologation of aldehydes to be achieved. ... 

H1 ftClNOi, N,0-Diacetyl-5-p-chloroanilino-4-hydroxy-penta-2,4-dienal, 40B, 117... 

The aroma of potato chips (French fries) is a mixture of more than 500 compounds. The important components are 2,3-diethyl-5-methylpyrazine, 2-ethenyl-3-ethyl-5-methylpyrazine, (2E,4Z)-deca-2,4-dienal, ( )-4,5-epoxydec-2-enal (8-183), l-octen-3-one, (Z)- and ( )-non-2-enal, 2-methylpropanal, 2-methylbutanal and 3-methylbutanal, biacetyl and 4-hydroxy-2,5-dimethyl-2f/-furan-3-one (furaneol). Another principal component is (Z)-2-(methylthiomethyl)but-2-enal (also known as 2-ethylidene methional, 8-198), which arises in the reaction of methional with acetaldehyde. Both isomers of 2-(methylthiomethyl)but-2-enal are used as flavour enhancers. Less signiflcant compounds are methanethiol and methional. 

P-Sitosterol and a bitter principle tamarin-dienal (5-hydroxy-2-oxo-hexa-3,5-dienal) are reported from the dried fruit pulp (ca. 0.67%)." ... 

Our strategy for the synthesis of (+)-dactylolide (2.217) is outlined in Scheme 2.69. We envisioned that the 20-membered macrolactone in 2.332 could be constructed by intramolecular iV-heterocyclic carbene (NHC)-catalyzed oxidative macrolactonization of co-hydroxy aldehyde 2.333. Intramolecular NHC-catalyzed oxidative esterification reactions have been recognized as an attractive tool and rapidly growing area in the synthetic community. Indeed, several examples of these reactions have recently been reported [208-216], which clearly provide a new opportunity for the development of catalytic acyl transfer agents in macrolactonization reactions of co-hydroxy aldehydes in the presence of oxidants. The substrate for the macrolactonization reaction would be derived firom the cyanohydrin alkylation of 2,6-dr-tetrahydropyran enal 2.335 with dienyl chloride 2.334. 2,6 -di-tetrahydropyran enal would in turn be constructed by employing the 1,6-oxa conjugate addition reaction of co-hydroxy 2,4-dienal 2.336. Despite the... 

A number of natural products or fragments of them have become available by nucleophilic additions to the aldehyde group of tricarbonyl(T -dienal)iron complexes. This includes ( )-5-hydroxy-6 , 8Z,l lZ,14Z-icosatetraenoic acid (5-HETE) methyl ester,(-)-LTA4 methyl ester, halicholactone, racemic lipoic acid methyl ester,macrolactin A fragments, the as-indacene unit of ikarugamycin, 1 l-(Z)-retinal, and the C11-C17 segment of soraphen Asymmetric variations... 

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