title: One-pot phosphine-catalyzed syntheses of quinolines.
abstract: In this study we developed an efficient one-pot procedure for the preparation of 3-substituted and 3,4-disubstituted quinolines from stable starting materials (activated acetylenes reacting with o-tosylamidobenzaldehydes and o-tosylamidophenones, respectively) under mild conditions. The reaction appears to operate under a general base catalysis mechanism, instigated by the β-phosphonium enoate α-vinyl anion generated in situ through nucleophilic addition of PPh(3) to the activated alkyne. Michael addition of the deprotonated tosylamides to the activated alkynes and subsequent rapid aldol cyclization led to the formation of labile N-tosyldihydroquinoline intermediates. Driven by aromatization, detosylation of the dihydroquinoline intermediates occurred readily in the presence of dilute aqueous HCl to give the final quinoline products.
authors.affiliation: Department of Chemistry and Biochemistry, University of California, Los Angeles, 607 Charles E. Young Drive East, Los Angeles, California 90095-1569, USA.
authors.forename: San
authors.initials: S
authors.lastname: Khong
authors.forename: Ohyun
authors.initials: O
authors.lastname: Kwon
mesh_terms: D000480:Alkynes / Q000737:chemistry*; D002384:Catalysis; D003500:Cyclization; D015394:Molecular Structure; D010720:Phosphines / Q000737:chemistry*; D011804:Quinolines / Q000138:chemical synthesis* / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D000480:Alkynes; D010720:Phosphines; D011804:Quinolines; C044646:phosphine