Akira Sera

Synthesis of C-nucleosides from non-carbohydrate precursors. A 2,4-dioxoimidazolidin-5-yl ribofuranoside

Abstract 3-Phenyl-2,4-dioxoimidazolidin-5-yl ribofuranoside (a hydantoin C-riboside) was synthesized from a Diels-Alder adduct of furan with methyl nitroacrylate.

1H nuclear magnetic resonance study of high-pressure effects on cis-trans interconversion of N-methyl-lactams

An increase in pressure has been found to provide a shift in the conformational equilibrium toward a higher s-cis population for 15-, 17-, and 20-membered-ring lactams, while a slight decrease in the s-cis population upon increase in pressure has been observed for an 11-membered-ring lactam. The results are interpreted in terms of the difference in the molecular shape and polarity of s-cis- and s-trans-isomers.

Synthesis of σ-(vinyl)iron(III) porphyrins and (dialkylcarbene)iron(II) porphyrins through the hydrometallation of alkynes with iron(III) porphyrins and NaBH4

Treatment of FeIII(tpp)Cl (tpp =meso-tetraphenylporphyrin dianion) with excess of NaBH4 and terminal alkynes in toluene–methanol afforded (dialkylcarbene)FeII(tpp), while the reaction with internal alkynes afforded σ-(vinyl)FeIII(tpp) in good yields.

The photoaddition of enaminoketonatoboron difluorides with trans-stilbene

The photochemical reactions of enaminoketonatoboron diflurides 1 with trans-stilbene gives cyclobutanes 2 and azetidines 3 in a regio- and stereo-specific manner.

Cycloaddition of 1-Methoxy-3-trimethylsilyloxybutadiene with Halogenated Carbonyl Compounds

Cycloadditions of 1-methoxy-3-trimethylsilyloxy-1,3-butadiene (1) with halogenated carbonyl compounds (2) yielded corresponding substituted tetrahydro- and/or dihydropyran-4-ones (3 and/or 4). Lewis acids were found to be effective as catalysts. Reactions with less reactive carbonyl compounds (2c,d) afforded p-hydroxyacetophenone (5) produced by cyclodimerization of 1. Stereochemistry of the adducts was deduced by 1 H nmr spectroscopy

Peptide synthesis under high pressure. Coupling reactions of N-(benzyloxdycarbonyl)amino acid N-hydroxysuccinimide esters with N-(carboxymethyl)amino acid diesters

Coupling reactions of N-(benzyloxycarbony)amino acid N-hydroxysuccinimide esters with N-(carboxymethyl)amino acid diesters are significantly accelerated by using high pressure (10 kbar).

Norrish type II photo-deacylation of semicyclic imides

The photochemical deacylation of 1,4-diacyl-2,5-piperazinediones was found to proceed through the type II ketene eliminating process

A simple synthesis of bicyclomycin skeleton

Synthese de dibenzyl-7,9 methylene-5 oxa-2diaza-7,9bicyclo [4.2.2] decanedione-8,10 a partir de dimethoxy-3,6 piperazinedione-2,5