5.6- Dihydro-2H-pyrane-2-ones

The rhodium-catalyzed asymmetric conjugate addition is applicable to a,yS-unsaturated esters (Scheme 3.8). Hayashi reported [20] that the reachon of 5,6-dihydro-2H-pyran-2-one 19a with phenylboronic acid gave a 94% yield of phenylated lactone (S)-20am with 98% enanhomeric excess. For the linear enoates, organoboronic acids did not give... 

Carlson, R. M. Oyler, A. R. Peterson, J. R. Synthesis of substituted 5,6-dihydro-2H-pyran-2-ones. Propiolic acid dianion as a reactive three-carbon nucleophile. J. Org. Chem. 1975, 40, 1610-1616. 

The other factor that may determine the type of cell death is the chemical structure of inducing agents [14]. We have recently found that u,(>-unsaluraled ketones such as 4,4-dimethyl-2-cyclopenten-l-one, a-methy-lene-y-butyrolactone, 5,6-dihydro-2H-pyran-2-one [15], codeinone [16], and morphinone [17] and a-hydroxylketones such as 3,3,3-trifluoro-2-hydroxy-1-phenyl-1-propanone induced caspase-independent cell death [18], induced vacuolization or autophagosome formation engulfing organelles, but without induction of apoptosis markers. 

Harries JM, Li M, Scott JG, O Doherty GA (2004) Approach to 5,6-dihydro-2H-pyran-2-one containing natural products. In Harmata M (ed) Strategies and tactics in oiganic synthesis, vol. 5. Elsevier, London... 

Hydroxyacetylenic acids. The dianion of propiolic acid (1) can be generated at -45° with LDA in 1 1 THF—HMPT solution. The dianion reacts with epoxides to form 5-hydroxyacetylenic acids (2) in moderate yields. The products can be converted into substituted 5,6-dihydro-2H-pyrane-2-ones, a ring... 

A. 5,6-Dihydro-2H-pyran-2-one [2H-Pyran-2-one, 5y6-dihydro-]. In a 500-ml., one-necked, round-bottomed flask equipped with a reflux... 

Matsuda, M., Y. Endo, S. Fushiya, T. Endo, and S. Nozoe Cytotoxic 6-Substituted 5,6-Dihydro-2H-pyran-2-ones from a Brazilian Medicinal Plant, Chorisia crispiflora. Heterocycles, 38, 1229 (1994). 

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