Yoshiaki Sugita

Two lactone formation reactions from 1,3-dioxin-4-ones having hydroxyalkyl group at the 6-position: Difference in ring opening and closure☆

Abstract Two methods (A: ring opening to acylketenes followed by intramolecular ketene trapping and B: methoxide-mediated ring opening followed by cyclization of the hydroxy esters thus formed) have become available for the synthesis of lactones and/or cyclic ethers from 1,3-dioxin-4-ones having 1-∼ 4-hydroxyalkyl group at the 6-position. Mechanism and scope of both methods have been clarified.

Lipase-catalyzed asymmetric synthesis of 6-(3-chloro-2-hydroxypropyl)-1,3-dioxin-4-ones and their conversion to chiral 5,6-epoxyhexanoates

Abstract Highly enantioselective syntheses of ( R )- and ( S )-6-(3-chloro-2-hydroxypropyl)-1,3-dioxin-4-ones by means of lipase-catalyzed kinetic resolutions are described. Chiral dioxinones thus obtained have been converted to optically active 5,6-epoxyhexanoates, which are important precursors for a series of biologically active compounds.

Aldol reaction of 4-trimethylsiloxy-6-methylene-1,3-dioxines with chiral aldehydes: Enantioselective synthesis of 1,3-dioxin-4-ones having a 2,3-dihydroxylated alkyl group at the 6-position

Abstract A novel enantioselective synthesis of 1,3-dioxin-4-ones having a 2,3-dihydroxylated alkyl group at the 6-position has been accomplished by titanium tetrachloride-mediated aldol condensation of silyl enol ethers derived from the 6-alkylated dioxinones with chiral 2-benzyloxypropanal. The keto group of the corresponding β-keto esters obtained after cleavage of the acetal function affords, by 1,3- syn and/or - anti reduction, 3,5,6-trihydroxyheptanoic acids in highly enantioselective manner.

Synthesis of 1,3-dioxin-4-ones having chiral hydroxyalkyl groups at the 6-position by means of baker's yeast reduction and their uses for epc synthesis

Abstract Prochiral methyl ketones connected with 6-(4-oxo-1,3-dioxinyl) group directly or through methylene chain (1–3) gave, by treatment with fermenting bakers yeast, the corresponding ( S )-alcohols which served as synthons for a variety of enantiomerically pure compounds.

Highly enantioselective reduction of acetoacetylated meldrum's acid with fermenting baker's yeast

Abstract Acetoacetylated Meldrums acid was enantioselectiviely reduced with fermenting bakers yeast to afford the corresponding chiral (S)-alcohol, which could be easily converted to δ-lactone derivatives.

Use of 1,3-dioxin-4-ones and related compounds in synthesis. Part 39. Enantioselective synthesis of 1,3-dioxin-4-ones having 2,3-dihydroxy- or 2,3,4-trihydroxyalkyl groups at the 6-position: versatile building blocks of polyhydroxylated 4–7 carbon backbones

1,3-Dioxin-4-ones having 3-hydroxyprop-1-enyl and 2-hydroxybut-3-enyl groups at the 6-position afford, after the Sharpless asymmetric epoxidation followed by epoxide ring cleavage, the 6-[(2S)-2,3-dihydroxypropyl]- and 6-[(2S,3R)-2,3,4-trihydroxybutyl)dioxinones. The former acts as a four-and six-carbon building block, while the latter as a five- and seven-carbon building block.

Enantioselective synthesis of (S)- and (R)-6-(2,3-dihydroxypropyl)-1,3-dioxin-4-ones: the versatile building blocks of four- and six-carbon backbones

The Sharpless asymmetric epoxidation of 2,2-dimethyl-6-(3-hydroxy-1-propenyl)-1,3-dioxin-4-one using titanium tetraisopropoxide–diisopropyl tartrate followed by catalytic hydrogenation affords the title compounds as enantiomerically pure compounds, which act as versatile four- and six-carbon building blocks.