Yoshizumi Yasui

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Synthesis of the pentacyclic core of ecteinascidin 743 is described. This synthesis features concise construction of the diazabicyclo[3.3.1]nonane skeleton using gold(I)-catalyzed one-pot keto amide formation, acid-promoted enamide formation, and oxidative Friedel-Crafts cyclization as the key steps.
A one-pot synthesis of C1-elongated amides starting from olefins and carbamoyl chlorides has been developed. Alkylboranes, generated by hydroboration of terminal olefins with 9-BBN-H, underwent smooth coupling with carbamoyl chlorides in the presence of palladium catalyst and Cs2CO3.
As a convenient and direct synthesis of 1,2-dihydroisoquinolines, the gold(I)-catalyzed intramolecular hydroamination of (2-alkynyl)benzyl carbamates has been developed. The reaction with cationic gold(I) complex [AuCl(PPh(3))/AgNTf(2)] proceeded at room temperature, giving the desired 6-endo adducts. The addition of alcohol efficiently promoted the(More)
A series of C-shaped, 1,1'-alkyl-bridged 4,4'-diaryl-2,2'-bibenzimidazoles has been synthesized. The crystal structures of these compounds have been determined and packing diagrams demonstrate that these molecules either form linear intercalated molecular chains or include solvent molecules in the solid state. Crystal structures are compared to(More)
Toward concise access to functionalized amides and lactams, palladium-catalyzed amidations of alkynes and alkenes with formamide derivatives were developed. Cyanoformamides having an alkynyl group were found to undergo intermolecular cyanoamidation in the presence of palladium catalyst to afford alpha-alkylidene lactams. Whereas, when cyanoformamides that(More)
Synthetic studies on vincorine are described; the conversion of 3-aminoethyl-3-alkyloxindoles to 3a,8a-dialkyl-1,2,3,3a,8,8a-hexahydropyrrolo[2,3-b]indoles has been achieved through an addition-cyclization sequence, and a fully functionalized key intermediate was constructed with this method.
An enantioselective intramolecular Heck-type reaction of chloroformamides has been developed for the synthesis of 3,3-disubstituted piperidones. The desired piperidone was formed in the presence of a palladium catalyst, an optically active phosphoramidite ligand, K3PO4 and Ag3PO4. The obtained piperidone was converted to epieburnamonine.
By using carbophilic Lewis acids, In(OTf)3, NiCl2, and AuCl(PPh3)/AgNTf2, a concise and efficient synthesis of 1,3-disubstituted 1,2-dihydroisoquinolines has been achieved via tandem nucleophilic addition and cyclization of 2-(1-alkynyl)arylaldimines. Addition of proton sources such as water, CF3CH2OH, and 2,6-di-tert-butyl-4-methoxyphenol was essential for(More)