title: Asymmetric organocatalyzed Michael addition of nitromethane to a 2-oxoindoline-3-ylidene acetaldehyde and the three one-pot sequential synthesis of (-)-horsfiline and (-)-coerulescine.
abstract: (-)-Horsfiline and (-)-coerulescine were synthesized through three one-pot operations in 33 and 46% overall yield, respectively. Key to the success was the efficient use of a diarylprolinol silyl ether to catalyze the asymmetric Michael addition of nitromethane to a 2-oxoindoline-3-ylidene acetaldehyde. This allowed the all-carbon quaternary, spirocyclic carbon stereocenter to be constructed in good yield with excellent enantioselectivity.
authors.affiliation: Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aramaki-Aza Aoba, Aoba-ku, Sendai 980-8578 (Japan), Fax: (+81) 22-795-6566 http://www.ykbsc.chem.tohoku.ac.jp.
authors.forename: Takasuke
authors.initials: T
authors.lastname: Mukaiyama
authors.forename: Kento
authors.initials: K
authors.lastname: Ogata
authors.forename: Itaru
authors.initials: I
authors.lastname: Sato
authors.forename: Yujiro
authors.initials: Y
authors.lastname: Hayashi
mesh_terms: D000079:Acetaldehyde / Q000737:chemistry*; D000814:Aniline Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D002384:Catalysis; D008697:Methane / Q000031:analogs & derivatives* / Q000737:chemistry; D009595:Nitroparaffins / Q000737:chemistry*; D013141:Spiro Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: D000814:Aniline Compounds; D009595:Nitroparaffins; D013141:Spiro Compounds; C480174:coerulescine; C443722:horsfiline; D000079:Acetaldehyde; D008697:Methane; C008640:nitromethane
keywords: Michael addition; alkaloids; asymmetric synthesis; one-pot reactions; organocatalysis