Design of Brønsted Acid-Assisted Chiral Brønsted Acid Catalyst Bearing a Bis(triflyl)methyl Group for a Mannich-Type Reaction
2006; American Chemical Society; Volume: 8; Issue: 15 Linguagem: Inglês
10.1021/ol060939a
ISSN1523-7060
AutoresAiko Hasegawa, Yuki Naganawa, Makoto Fushimi, Kazuaki Ishihara, Hisashi Yamamoto,
Tópico(s)Organic Chemistry Cycloaddition Reactions
Resumo[Structure: see text] A new Brønsted acid-assisted chiral Brønsted (chiral BBA) acid catalyst (1) was developed by substituting a hydroxy group of optically active 1,1'-bi(2-naphthol) with a stronger Brønsted acidic group such as a bis(trifluoromethanesulfonyl)methyl group. The enantioselective Mannich-type reaction of ketene silyl acetals with aldimines catalyzed by (R)-1 in the presence of stoichiometric achiral proton sources gave (S)-beta-amino esters in high yield with moderate to good enantiomeric excesses.
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