Phosphine-Triggered Selectivity Switch in Silver-Catalyzed o-Alkynylbenzohydroxamic Acid Cycloisomerizations.
A silver-catalyzed cycloisomerization reaction of a series of o-alkynylbenzohydroxamic acids is reported. Several 5-exo-dig and 6-endo-dig modes of cyclization were observed with the nitrogen or oxygen atoms of the amide group acting as nucleophiles. The selectivity was strongly dependent on the silver salt used and on the presence of triphenylphosphine as an additive. Indeed, while the use of Ag2O at room temperature allowed the isolation of isobenzofuran-1-one oximes (7 compounds, 48-92% yield), [Ag(Im)]nwith the concomitant addition of 2 equiv of PPh3led to a switch in selectivity and to a family of isoindolin-1-ones (10 compounds, 59-87%).
Institut Curie, UMR CNRS 176 , 26 rue d'Ulm, 75005 Paris, France.
Xavier
X
Bantreil
Institut Curie, UMR CNRS 176 , 26 rue d'Ulm, 75005 Paris, France.
Aurélie
A
Bourderioux
Université de Lyon , Laboratoire de Synthèse et Méthodologie Organiques (LSMO), UMR CNRS 5246, 43 boulevard du 11 novembre 1918, 69622 Villeurbanne, France.
Pierre
P
Mateo
Institut Curie, UMR CNRS 176 , 26 rue d'Ulm, 75005 Paris, France.
Caroline E
CE
Hagerman
Université Paris Descartes , Faculté de Pharmacie de Paris, UMR CNRS 8015 & UMR CNRS 8638, 4 avenue de l'Observatoire, 75006 Paris, France.
Mohamed
M
Selkti
Université Paris Descartes , Faculté de Pharmacie de Paris, UMR CNRS 8015 & UMR CNRS 8638, 4 avenue de l'Observatoire, 75006 Paris, France.
Etienne
E
Brachet
Institut Curie, UMR CNRS 176 , 26 rue d'Ulm, 75005 Paris, France.|Université Paris Descartes , Faculté de Pharmacie de Paris, UMR CNRS 8015 & UMR CNRS 8638, 4 avenue de l'Observatoire, 75006 Paris, France.
Philippe
P
Belmont