Sakae Aoyagi

Asymmetric synthesis of 2-substituted pyrrolidines and piperidines by nucleophilic addition to N-acyliminium ions bearing pyrrolidine chiral auxiliaries

Abstract Addition of carbon nucleophiles to cyclic N -acyliminium salts chirally modified by various optically active pyrrolidines leads to highly enantioselective synthesis of 2-substituted pyrrolidines and piperidines.

Total synthesis of the proposed structure of lepadiformine via intramolecular N-acylnitroso Diels–Alder reaction

Abstract A stereocontrolled approach to the proposed structure of lepadiformine has been achieved employing an intramolecular hetero Diels–Alder reaction of an N-acylnitroso compound, in which syn-face selectivity was controlled. The NMR data of the product synthesized based on this approach is not identical with those reported for natural lepadiformine. Thus, the proposed structure for natural lepadiformine must be revised.

Total synthesis of (−)-pumiliotoxin C by aqueous intramolecular acylnitroso Diels-Alder approach

Abstract A chiral approach to (−)-pumiliotoxin C via a stereoselective intramolecular hetero Diels-Alder reaction of a chiral acylnitroso compound performed in an aqueous medium is described.

Enhanced stereoselectivity in aqueous intramolecular hetero Diels-alder cycloaddition of chiral acylnitroso compounds

Abstract In an aqueous medium, intramolecular hetero Diels-Alder cycloadditions of the chiral acylnitroso compounds, generated from the chiral hydroxamic acids by in situ periodate oxidation, shows a pronounced enhancement of the trans selectivity compared with the results obtained by employing nonaqueous conditions.

ASYMMETRIC TOTAL SYNTHESIS OF (-)-EPIBATIDINE

Abstract An enantioselective approach to (−)-epibatidine based on asymmetric hetero Diels-Alder cycloaddition with an N -acylnitroso dienophile bearing 8-(2-naphthyl)menthol as a chiral source, wherein π-π stacking interaction between the naphthyl and nitrosocarbonyl groups may contribute to facial control, is described.

Palladium(II)-Catalyzed Tandem Cyclic Carbopalladation-Vinylation of Enyne Compounds

Abstract Upon treatment with catalytic Pd2(dba)3•CHCl3 in the presence of AcOH, the enyne compounds were subjected to hydropalladation followed by cyclic carbopalladation to form the homoallylpalladium complexes, which subsequently underwent in situ Stille type cross coupling with various vinyltin reagents to give the cyclized products bearing allyl appendages.

Lewis acid-mediated nucleophilic alkylations on chiral [6,3a,4]oxadiazaindano[5,4-a]isoquinolines. Asymmetric synthesis of 1-alkyl substituted tetrahydroisoquinolines

Abstract Lewis acid-mediated nucleophilic alkylation of the chiral [6,3a,4]oxadiaza-indano[5,4-α]isoquinoline derivatives with various organometallic reagents leads to highly enantioselective synthesis of 1-alkyl substituted tetrahydroisoquinolines. This methodology was applied to the asymmetric synthesis of (−)-salsolidine and (+)- O -methylarmepavine.

Asymmetric synthesis of 1-substituted tetrahydroisoquinolines by nucleophilic addition to hydrazonium ions. Application to the enantioselective syntheses of (+)- and (−)-salsolidines and (−)-cryptostyline II

Abstract Nucleophilic addition of carbon nucleophiles and metal hydride reagents to hydrazonium salts modified by optically active 2-substituted pyrrolidine auxiliaries leads to highly enantioselective synthesis of 1-substituted tetrahydroisoquinolines. This methodology was applied to asymmetric synthesis of the title isoquinoline alkaloids.

Enantioselective synthesis of (R)-(−)-Cryptopleurine

Abstract An enantioselective synthesis of naturally occurring ( R )-(−)-cryptopleurine based on highly efficient asymmetric amidoalkylation using a cyclic N -acyliminium intermediate is described.

Total synthesis of (−)-nupharamine and (+)-3-epinupharamine via asymmetric nitroso Diels-Alder reaction

Chiral synthesis of (−)-nupharamine and (+)-3-epinupharamine, based on elaboration of the intramolecular asymmetric Diels-Alder reaction of N-acylnitroso compounds and the introduction of the furyl group in a fully stereocontrolled manner, is described.