title: Highly enantioselective and efficient synthesis of flavanones including pinostrobin through the rhodium-catalyzed asymmetric 1,4-addition.
abstract: An efficient synthesis of bioactive chiral flavanones (1) was achieved through the Rh-catalyzed asymmetric 1,4-addition of arylboronic acid to chromone. The reaction in toluene proceeded smoothly at room temperature in the presence of 0.5% Rh catalyst with electron-poor chiral diphosphine MeO-F(12)-BIPHEP. In this reaction, the 1,2-addition to (S)-1 frequently occurred to yield (2S,4R)-2,4-diaryl-4-chromanol as a byproduct, which could be reduced by changing the reaction solvent to CH(2)Cl(2) to deactivate the Rh catalyst (3% required).
authors.affiliation: Division of Chemistry and Biochemistry, Graduate School of Natural Science and Technology, Okayama University, 3-1-1 Tsushima-naka, Okayama 700-8530, Japan. korenaga@cc.okayama-u.ac.jp
authors.forename: Toshinobu
authors.initials: T
authors.lastname: Korenaga
authors.forename: Keigo
authors.initials: K
authors.lastname: Hayashi
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Akaki
authors.forename: Ryota
authors.initials: R
authors.lastname: Maenishi
authors.forename: Takashi
authors.initials: T
authors.lastname: Sakai
mesh_terms: D002384:Catalysis; D044950:Flavanones / Q000138:chemical synthesis* / Q000737:chemistry; D015394:Molecular Structure; D012238:Rhodium / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D044950:Flavanones; D012238:Rhodium; C411294:pinostrobin