Naoaki Kanaya

Studies on the syntheses of heterocyclic compounds. Part 876. The chiral total synthesis of brevianamide E and deoxybrevianamide E

The chiral total synthesis of brevianamide E (1) and deoxybrevianamide E (2) starting from L-proline is described. Condensation of 2-(1,1-dimethylallyl)-3-dimethylaminomethylindole (3) and (–)-methyl 1,4-dioxoperhydropyrrolo[1,2-a]pyrazine-3-carboxylate (7) derived from L-proline followed by demethoxycarbonylation gave (–)-deoxybrevianamide E (2) and its epimer (10). Photo-oxygenations of (2) and (10) formed (–)-brevianamide E (14) and its three stereoisomers (15), (16), and (17). The absolute stereochemistry of brevianamide E (14) was determined as 4aS,5aR,10aS,11aS by this synthesis.

Ring expansion reactions of penicillin derivatives by rhodium-catalyzed decomposition of diazoketones ??? stereoselective syntheses of eight-membered oxa-β-lactams

Abstract The reaction of penicillin derivatives (1 – 3) with p -nitrobenzyl α-diazoacetoacetate (8) in the presence of a catalytic amount of rhodium acetate afforded the corresponding ring-expanded oxa-derivatives (5 – 7) stereoselectively, in moderate yields.

A stereoselective synthesis of corynantheine-type alkaloids via enamine annulation. Total synthesis of (±)-dihydrocorynantheol and formal total synthesis of (±)-corynantheine and (±)-ajmalicine

Enamine annulation between 3,4-dihydro-1-methyl-β-carboline (4) and dimethyl 3-methoxyallylidenemalonate (5) yielded 2-(2,2-dimethoxyethyl)-2,3,4,6,7,12-hexahydro-3-methoxycarbonyl-4-oxoindolo [2,3-a]quinolizine (6), which was transformed into (±)-dihydrocorynantheol (1). (±)-Corynantheal (19), which is convertible into (±)-corynantheine (2) and (±)-ajmalicine (3), was stereoselectively synthesised from (6)via empimerisations at the angular position using Adams catalyst.

Synthesis and biological activities of new HMG-CoA synthase inhibitors: 2-oxetanones with a side chain containing biphenyl, terphenyl or phenylpyridine

A series of 1233A analogs containing biphenylyl, terphenylyl or phenylpyridyl groups in their side chain were synthesized and tested for the inhibitory activities against 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) synthase and inhibition for the cholesterol biosynthesis in the mouse liver. The compounds with an oxetane, cyclobutanone or γ-butyrolactone ring as isosters of a 2-oxetanone ring were entirely inactive. Among synthetic analogs, anti-4-[3-[2-(5-isopropyl-2-pyridyl)-ethyl]-phenyl]ethyl]-3hydroxymethyl-2-oxetanone (10b) was most active in vitro. The structure activity relationships on the transformations of 2-oxetanone and its side chain were obtained

Novel transformation of penicillin into penem nucleus : synthesis of 2-carboxylpenem derivative

Abstract A novel transformation of 6-aminopenicillanic acid (6-APA) into penem derivative is described.