Takeshi Wakamatsu

A Convenient Synthesis of Juglone Via Neutral Salcomine Oxidation

Abstract 1,5-Dihydroxynaphthalene and its derivatives can be oxidized by molecular oxygen in the presence of catalytic amounts of salcomine under neutral conditions to afford the corresponding 1,4-naphthoquinones as the major products.

A synthesis of novel nine-membered dienones through a cyclic acetylenic oxy-cope rearrangement: The synthesis of dl-phoracantholide I

Abstract Phoracantholide I, having a ten-membered lactone, was synthesized through a new synthetic method which includes a cyclic acetylenic oxy-Cope rearrangement and ring-expansion by the Baeyer-Villiger oxidation of a nine-membered ketone.

Total syntheses of the metabolites of schizandrin

Abstract The total syntheses of the metabolites of schizandrin were achieved. The tetracyclic lactone intermediates (13a–e) were prepared in optically pure form by the oxidative coupling reaction of the corresponding 3-benzyl-1-benzylidenebutyrolactones. Mukaiyama hydration of 13b afforded hydroxylactone ( 14 ), which was converted into SZ-M3 (4). The introduction of C6,7-diol moiety, which is common to the metabolites ( 4–11 ), was carried out by the successive double bond migration to 15a–e , lactone ring reduction to the allylic diols ( 32a–e ), and glycol formation. Then, reduction of the mesylates 33 completed the syntheses of the metabolites.

Syntheses of (±)-pyrenophorin and (±)-colletallol

Abstract Pyrenophorin 1 and colletallol 3 were synthesized in their racemic forms from the corresponding hydroxycarboxylic acids 9 and 14 via stereoselective formation of the requisite trans double bonds after macrocyclization.

Synthesis of optically pure gomisin A and schizandrin: The first total synthesis of gomisin A and schizandrin having naturally occurring configurations

Abstract The total synthesis of gomisin A and schizandrin having natural configurations were accomplished for the first time. The key feature of these syntheses is a highly efficient intramolecular oxidative coupling of the intermediates 9 and 21 , which can be obtained as both enantiomers in optically pure forms. The manipulation of the lactone moieties of 7 and 22 afforded natural enantiomers of schizandrin and gomisin A.

A practical method for the oxidative coupling of aromatic compounds

Abstract A practical method for the oxidative coupling reaction of phenolic and nonphenolic compounds is described. The versatility of this reaction was demonstrated by the successful coupling of the wide variety of substrates including catecholic compounds and known intermediates for the synthesis of steganacin and its analogs.

First total synthesis of optically pure deoxyschizandrin and wuweizisu C. The thermal stability of biaryl configuration

The total synthesis of deoxyschizandrin (1) and wuweizisu C (2) having natural configuration was accomplished and the thermal stability of biaryl configuration was confirmed.

A novel antileukemic sesquiterpene lactone: synthesis of racemic eriolanin

Abstract The synthesis of dl-eriolanin 1, highly oxygenated 1,10-seco-eudesmanolide isolated from the chloroform extracts of Eriophyllum lanatum Forbes (Compositae), is reported.

The oxirane ring openings of the dianhydro sugar with high regioselectivity and its use in preparation of two chiral segments of 6-deoxyerythronolide B

Abstract The oxirane ring of the dianhydro sugar 2 obtained from levoglucosan (1,6-anhydro-β-D-glucose) is opened regioselectively with organometallic carbon nucleophiles and its application to an asymmetric synthesis of the C 1 –C 5 segment 9 together with the C 9 -C 15 unit 18 of 6-deoxyerythronolide B 1 is described.

Synthetic studies on antibiotic macrodiolide: Synthesis of the a-segment of elaiophylin

Abstract A-segment(C11,-C15) containing L-oliose moiety in both side of elaiophylin(1) was synthesized enantio- and stereoselectively in the form of (4) which involves 7 asymmetric carbons of seco acid, by a coupling of the fragment (2) with (3). These chiral fragments were prepared from methyl-α-D-glucopyranoside(5) or levoglucosan(1,6-anhydro-β-D-glucopyranose) (10), respectively.