Noritaka Chida

A chemoselective approach for the total synthesis of (±)-gephyrotoxin has been developed. The key to success was the utilization of N-methoxyamides, which enabled the direct coupling of the amide with an aldehyde and selective reductive nucleophilic addition to the amide in the presence of a variety of sensitive and electrophilic functional groups, such as a methyl ester. This chemoselective approach minimized the use of protecting-group manipulations and redox reactions, which resulted in the m

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTTotal synthesis of antibiotic hygromycin ANoritaka Chida, Masami Ohtsuka, Keiichi Nakazawa, and Seiichiro OgawaCite this: J. Org. Chem. 1991, 56, 9, 2976–2983Publication Date (Print):April 1, 1991Publication History Published online1 May 2002Published inissue 1 April 1991https://pubs.acs.org/doi/10.1021/jo00009a009https://doi.org/10.1021/jo00009a009research-articleACS PublicationsRequest reuse permissionsArticle Views977Altmetric-Citations81LEARN ABOUT

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTTotal synthesis of (+)-lycoricidine and its 2-epimer from D-glucoseNoritaka Chida, Masami Ohtsuka, and Seiichiro OgawaCite this: J. Org. Chem. 1993, 58, 16, 4441–4447Publication Date (Print):July 1, 1993Publication History Published online1 May 2002Published inissue 1 July 1993https://pubs.acs.org/doi/10.1021/jo00068a045https://doi.org/10.1021/jo00068a045research-articleACS PublicationsRequest reuse permissionsArticle Views1075Altmetric-Citations77LEAR

Abstract Conversion of hex-5-enopyranosides into substituted cyclohexanones (Ferrier rearrangement) was found to proceed efficiently with a catalytic amount of various mercury(II) salts at room temperature in a neutral solvent system. Among the mercury(II) salts tested, mercury(II) trifluoroacetate showed the highest activity. Four optically active cyclohexenones were prepared from hex-5-enopyranosides utilizing this method.

The chiral and stereoselective synthesis of (+)-lactacystin 1, the first non-protein neurotrophic factor, is described; the γ-lactam portion possessing a quaternary carbon in 1 was constructed stereoselectively from D-glucose using the allylic trichloroacetimidate rearrangement (Overman rearrangement) as the key reaction.

An iridium-catalyzed reductive nucleophilic addition to secondary amides is reported. After the iridium-catalyzed reduction, the resulting imines can undergo the Strecker reaction, the Mannich reaction, allylation, and [3 + 2]-cycloaddition. The method shows high chemoselectivity in the presence of other functional groups such as methyl ester.

An approach to cyclic nitrones from N-hydroxylactam derivatives is documented. The nucleophilic addition of an organolithium reagent to an N-OSEM [SEM=2-(trimethylsilyl)ethoxymethyl] lactam forms a five-membered chelated intermediate, which undergoes both elimination and deprotection to give a fully substituted nitrone in a one-pot process. When combined with the N-oxidation of easily available chiral lactams, this method becomes especially useful for the quick synthesis of chiral nitrones in en

The total synthesis of the antifungal antibiotic, polyoxin J 1 starting from myo-inositol is described; the two key components, 2 and 3, were prepared from a pair of optically resolved myo-inositol derivatives 4L and 4D, respectively, using a highly regioselective Baeyer–Villiger reaction, and finally coupled to complete the total synthesis.

The chiral and stereoselective synthesis of antimitotic phenanthridone alkaloids, (+)-7-deoxypancratistatin (1) and (+)-7-deoxytrans-dihydronarciclasine (2) is described.Both natural products were synthesized from the common compound (4), which had been prepared from D-glucose and employed for the synthesis of lycoricidine (3).The highly oxygenated phenanthridone alkaloids,l represented by pancratistatin?a7-deoxypancratistatin(1),2b 7-deoxy-trans-dihydronarciclasine (t)?c and lycoricidine (3)2d

A chirality transfer approach using acyclic polyol intermediates for the synthesis of (+)-neostenine (1) has been developed. The sequential Overman/Claisen rearrangement of an allylic 1,2-diol was especially useful, installing two contiguous stereocenters with complete diastereoselectivity in a one-pot sequence. The SmI₂ -mediated cyclization and the subsequent chemoselective reduction of a lactam moiety accomplished the first enantioselective total synthesis of (+)-neostenine (1).