Shin-ichi Kodato

Oxidative dimerization of Nb-acyltryptophans total synthesis and absolute configuration of ditryptophenaline

Abstract First total synthesis of ditryptophenaline 1 is described and the absolute configuration was determined.

Total synthesis of (+)-fumitremorgin B, its epimeric isomers, and demethoxy derivatives

Total synthesis of the title compounds is described. The key intermediate, dehydro-pentacyclic 13, is prepared in a sequence involving Pictet-Spengler reaction and DDQ oxidation. The key step in the synthesis was the dihydroxylation of 13 to afford the cis-diol 54, which was performed by direct oxidation with osmium tetroxide, whereas treatment of 13 with N-bromo-succinimide provided the trans-diol 41. Subsequent selective prenylation of 41 and 54 gave 13-epi-fumitremorgin B (45) and fumitremorgin B (1), respectively. 13-Epi-compound 45 is also converted into fumitremorgin B (1) by oxidation followed by reduction.

Synthetic approach to the total synthesis of fumitremorgins II synthesis of optically active pentacyclic intermediates and their dehydrogenation

Abstract Optically active pentacycles ( 13–18 ) were synthesized from L- and D-tryptophans, two of which ( 13 and 15 ) were alkylated and dehydrogenated to 21 and 22 , respectively.

Total synthesis and determination of absolute configuration of cerebroside B1b and its stereoisomers

Abstract First total synthesis of (+)-cerebroside B 1b , 1b , was described, the absolute configuration of which was determined to be (2S,3R)-1-O-β-D-glucopyranosyl-2-N-(2′R)-2′-hydroxypalmitoyl-sp hinga-4E,8Z-dienine.

Synthesis of cerebroside B1b with antiulcerogenic activity I. Synthesis of ceramides with optically active α-hydroxypalmitic acids.

Abstract Synthesis of four diastereomeric ceramides including the aglycone of cerebroside B 1b ( 1b ) was described. The crucial step in the synthesis of cerebroside B 1b consists in a regio- and stereoselective formation of the erythro-sphingosine moiety by the reaction of dienal 4 with 2-nitroethanol followed by resolution with optically active α-hydroxypalmitic acids.

Synthesis of cerebroside B1b with antiulcerogenic activity II. Total synthesis and determination of absolute configuration of cerebroside B1b and its stereoisomers

Abstract First total synthesis of optically active cerebroside B1b (1b) is described. The absolute configuration of 1b was determined to be (2 S ,3 R ,4 E ,8 Z ,2′ R )-1- O -(β-D-glucopyranosyl)- N -(2′-hydroxyhexadecanoyl)-4,8-sphingadienine.