Pd-catalyzed intramolecular addition of active methylene compounds to alkynes, followed by subsequent cross-coupling with (hetero)aryl bromides and chlorides. The reaction proceeds under mild conditions, providing excellent functional group tolerance, including unprotected OH, NH2 groups, enolizable ketones, or a variety of heterocycles. Mechanistic studies point towards a catalyticcycle involving oxidative
3,5-Bis(pentafluorosulfanyl)phenylboronic acid: A new organocatalyst for Conia-ene carbocyclization of 1,3-dicarbonyl compounds having terminal alkynes
3,5-Bis(pentafluorosulfanyl)phenylboronic acid 1 was introduced as an efficient organocatalyst for Conia-ene carbocyclization of 1,3-dicarbonyl compounds having terminal alkynes. A variety of 2-alkynic 1,3-dicarbonyl compounds were smoothly converted to ene-carbocyclization products in moderate to excellent yields. Compared with the reported catalyst, 3-nitro phenylboronic acid, catalyst 1 is slightly better in a non-polar solvent such as toluene and Solkane(R) 365mfc (1,1,1,3,3-pentafluorobutane). These results indicate that the SF5 function can be a lipophilic and sterically demanding alternative to the NO2 group in catalyst design. (C) 2012 Elsevier B.V. All rights reserved.