Munenori Inoue

An efficient synthesis of (+)-aureol via boron trifluoride etherate-promoted rearrangement of (+)-arenarol

A novel marine natural product, (+)-aureol (1), was efficiently synthesized starting from the cis-fused decalin derivative 4. The synthetic method features boron trifluoride etherate-promoted rearrangement/cyclization reaction of (+)-arenarol (2) to form (+)-aureol (1) with complete stereoselectivity in high yield. (+)-Arenarol (2) was prepared in an alternative and more efficient manner employing salcomine oxidation protocol.

Synthetic studies on Sch 202596, an antagonist of the galanin receptor subtype GalR1: an efficient synthesis of (±)-geodin, the spirocoumaranone part of Sch 202596

Abstract An efficient and facile synthesis of (±)-geodin [(±)-2 ] corresponding to the spirocoumaranone part of Sch 202596 ( 1 ) was accomplished in a convergent manner. The synthetic method features (i) a coupling reaction of the aryl aldehyde 6 with the aryl lithium 7 generated in situ from the aryl bromide 8 to deliver the highly substituted diaryl methanol 24 ( 6 + 7 → 24 ) and ii) oxidative spirocyclization reaction of the benzophenone 4 to construct the requisite spirocoumaranone skeleton [ 4 →(±)-2 ] as the key steps. The aromatic segments 6 and 8 were prepared from commercially available methyl 3,5-dihydroxybenzoate ( 9 ) and 5-methylresorcinol ( 10 ), respectively.

Studies toward the total synthesis of (−)-kampanol A: an efficient construction of the ABCD ring system

Abstract The optically active tetracyclic ABCD ring system 2 of (−)-kampanol A ( 1 ), a novel Ras farnesyltransferase inhibitor from a microorganism, was efficiently synthesized starting from the known ketol 4 as a model study. The synthetic method involves conjugate addition reaction of the Grignard reagent of the bromobenzene derivative 14 to the α-methylene ketone 10 to form the coupling product 15 and phenylselenium-mediated cyclization reaction of the phenol derivative 17 to stereoselectively construct the requisite tetracyclic intermediate 18 as the pivotal steps.

Toward the synthesis of phomoidride D.

An efficient and highly stereoselective approach toward the phomoidride family of natural products is described. The carbocyclic core structure was assembled using a tandem phenolic oxidation/Diels-Alder cycloaddition and a tandem 5-exo-trig/5-exo-trig radical cyclization to deliver an isotwistane intermediate that, upon a late-stage xanthate-initiated Grob fragmentation, furnishes the requisite bicyclo[4.3.1]decene.

Model studies toward scyphostatin: Synthesis of (S)-4-benzyl-3-(p-toluenesulfonyl)-2-oxazolidinone and its effective transformation to (S)-N-(1-benzyl-2-hydroxyethyl)hexadecanamide

(S)-4-Benzyl-3-(p-toluenesulfonyl)-2-oxazolidinone (6) was synthesized as a simplified model substrate for the cyclohexenone subunit (2) of scyphostatin (1) starting from L-phenylalanine (3). Transformation of 6 to (S)-N-(l-benzyl-2-hydroxyethyl)hexadecanamide (10) was efficiently achieved to develop a reliable protocol for the construction of the fatty acid-substituted aminopropanol side chain moiety present in 1; the method involves hydrolysis of the cyclic carbamate moiety, N-palmitoylation of the liberated N-Ts-amido function, and removal of the N-Ts protecting group as the crucial steps.