Synlett 2015; 26(16): 2301-2305
DOI: 10.1055/s-0035-1560090
letter
© Georg Thieme Verlag Stuttgart · New York

Asymmetric Michael Addition Reaction of α-Aryl-Substituted Lactams Catalyzed by Chiral Quaternary Ammonium Salts Derived from Cinchona Alkaloids: A New Short Synthesis of (+)-Mesembrine

Shiori Nunokawa
Laboratory of Natural Products Chemistry, Faculty of Science, Kochi University, Akebono-cho, Kochi 780-8520, Japan   eMail: kotsuki@kochi-u.ac.jp
,
Masamitsu Minamisawa
Laboratory of Natural Products Chemistry, Faculty of Science, Kochi University, Akebono-cho, Kochi 780-8520, Japan   eMail: kotsuki@kochi-u.ac.jp
,
Keiji Nakano
Laboratory of Natural Products Chemistry, Faculty of Science, Kochi University, Akebono-cho, Kochi 780-8520, Japan   eMail: kotsuki@kochi-u.ac.jp
,
Yoshiyasu Ichikawa
Laboratory of Natural Products Chemistry, Faculty of Science, Kochi University, Akebono-cho, Kochi 780-8520, Japan   eMail: kotsuki@kochi-u.ac.jp
,
Hiyoshizo Kotsuki*
Laboratory of Natural Products Chemistry, Faculty of Science, Kochi University, Akebono-cho, Kochi 780-8520, Japan   eMail: kotsuki@kochi-u.ac.jp
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Publikationsverlauf

Received: 02. Juli 2015

Accepted after revision: 16. Juli 2015

Publikationsdatum:
01. September 2015 (online)


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Abstract

The enantioselective Michael addition reaction of α-aryl-substituted lactams with electron-deficient olefins was efficiently catalyzed using chiral quaternary ammonium salts derived from cinchona alkaloids. This method was highly useful for the construction of an all-carbon-substituted quaternary carbon stereogenic center at the α-position of lactams in good to high yields and with good enantiomeric excess and could be applied to the short synthesis of (+)-mesembrine.

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