Takehiko Iida

Cyclocondensation of oxalyl chloride with 1,2-glycols

Abstract Oxalyl chloride reacts with a wide range of acyclic 1,2-glycols 1 in the presence of triethylamine to produce 1,3-dioxolan-2-ones 3 together with 1,4-dioxane-2,3-diones 2. Ethylene glycol (1d), monosubstituted ethylene glycols 1e, j—l, and erythro-1,2-disubstituted ethylene glycols 1f, m, o provide the cyclic carbonates 3 as the minor products, while the threo-compounds 1g, i, n, p, q and pinacol (1h) afford 3 as the main products. The formation of 3 may be rationalized in terms of stereoelectronically controlled cleavage of the conjugate base 17− of the tetrahedral intermediates. The rate for the conformational change of 17− into 18− and the equilibrium constant between these conformers are proposed to be the major factors affecting the reaction pattern.

Synthesis of [R-(R∗,S∗)]- and [S-(R∗,R∗)]β-hydroxy-3-(β-d-ribofuranosyl)-wybutines, the most probable alternatives for the hypermodified nucleoside of rat liver phenylalanine transfer ribonucleic acid

Abstract The synthesis of the title compounds started with the Vilsmeier reaction of 3-[2,3,5- tris -O-(tert- butyldimethylsilyl)-β- d - ribofuranosyl]wye ( 5b ) and proceeded through the Wittig reaction with ( R )- N -(methoxycarbonyl)-3-(triphenylphosphonio)alaninate ( 4 ), methylation with trimethylsilyldiazomethane, OsO 4 oxidation, cyclocondensation with triphosgene, and catalytic hydrogenolysis. Chromatographic separation of the resulting diastereomeric mixture and subsequent deprotection afforded the two desired nucleoside [ [R-(R ∗ ,S ∗ )]- and [S-(R ∗ ,R ∗ )]- 2b ] for the first time.

Synthesis of β-hydroxywybutines, the most probable alternatives for the hypermodified base of rat liver phenylalanine transfer ribonucleic acid☆

Abstract Deoxygenation of the 1,2-glycol (±)-5 was achieved at the position adjacent to the heterocycle through the cyclic carbonate (±)-14, providing the monohydroxy compound 6. This new method of regioselective deoxygenation was employed for the first synthesis of β-hydroxywybutines [[R-(R ∗ ,S ∗ )]- and [S-(R ∗ ,R ∗ )]-2] : oxidation of the methyl butenoate 7 with osmium tetroxide, followed by deoxygenation through the cyclic carbonates (19 and 20), afforded the two diastereomers of 2.

Synthesis of the cyclic oxalates of 1,2-glycols by controlling the formation of the cyclic carbonates

Cyclic oxalates 2 have been efficiently synthesized by the reaction of 1,2-glycols 1 with oxalyl chloride in the presence of pyridine or 2,4,6-trimethylpyridine, rather than triethylamine, or by reaction with 1,1′-oxalyldiimidazole.