title: Synthesis of 1,4-dihydrophosphinoline 1-oxides by acid-promoted cyclization of 1-(diphenylphosphoryl)allenes.
abstract: 1-(Diphenylphosphoryl)alka-1,2-dienes (phosphonoallenes) in Brønsted (super)acids (TfOH, FSO3H, H2SO4) gave the corresponding 1,2-oxaphosphol-3-enium ions, that were studied by means of NMR and DFT calculations. Upon hydrolysis of reaction solution, these cations afforded 3-hydroxyalk-2-en-1-yl-diphenylphosphine oxides (phosphonoallyl alcohols). But in (super)acids the cations were slowly transformed into O-protonated forms of 1-phenyl-1,4-dihydrophosphinoline 1-oxides, which were monitored by NMR. The latter phosphaheterocycles can be directly obtained from phosphonoallenes under the action of Lewis acid AlCl3.
authors.affiliation: Department of Organic Chemistry, Institute of Chemistry, Saint Petersburg State University, Universitetskaya nab., 7/9, Saint Petersburg, 199034, Russia.
authors.forename: Alexander S
authors.initials: AS
authors.lastname: Bogachenkov
authors.forename: Albina V
authors.initials: AV
authors.lastname: Dogadina
authors.forename: Irina A
authors.initials: IA
authors.lastname: Boyarskaya
authors.forename: Vadim P
authors.initials: VP
authors.lastname: Boyarskiy
authors.forename: Aleksander V
authors.initials: AV
authors.lastname: Vasilyev