Rhodium-Catalyzed Addition of Alkynes to Activated Ketones and Aldehydes

Abstract

[reaction: see text] The rhodium-catalyzed addition of alkynes to 1,2-diketones, 1,2-ketoesters, and aldehydes provides a method for the synthesis of tertiary alkynyl alcohols under mild conditions. The reaction tolerates many functional groups (such as carboxylic acids) that are incompatible with other methods. The alkyne addition reaction proceeds best using bulky phosphine ligands such as 2-(di-tert-butylphosphino)biphenyl. This method fills a void in the more common zinc-catalyzed processes, which give poor yields with enolizable 1,2-dicarbonyl substrates.

Pt-catalyzed cyclization/migration of propargylic alcohols for the synthesis of 3(2H)-furanones, pyrrolones, indolizines, and indolizinones

“…Investigations of this transformation began with alkynyl ketone 5 (Scheme 2), which was available in one-step from 3,4-hexanedione using the method of Chisholm. 12 Our past success using PtCl 2 as a carbophilic Lewis acid to mediate transformations involving alkynes 13 made it a starting point of our investigations.…”

Biarylphosphanliganden in der palladiumkatalysierten Aminierung

“…1998 haben wir eine neue Klasse luftbeständiger [1] Liganden mit DialkylbiarylphosphanGerüst eingeführt. [2] Als Liganden für Gold, [3][4][5][6][7][8][9][10][11] Silber, [12] Rhodium, [13,14] Ruthenium [15][16][17] und Kupfer [18] verbesserten diese Phosphane die Reaktivität und Katalysatorstabilität. Die weitaus größte Bedeutung hatten sie aber für palladiumkatalysierte Reaktionen wie die Sonogashira-, [19] Negishi-, [20] Hiyama-, [21][22][23] Kumada- [24] und Suzuki-Kreuzkupplung [25][26][27][28][29][30] , die Heck-Reaktion, [31][32][33] die Enolatarylierung [34][35][36][37] und -allylierung, [38] die reduktive Cyclisierung [39] und Veretherung, [40][41][42][43] die Silylierung, [44] Borylierung, [45][46][47] Cyanier...…”

Biaryl Phosphane Ligands in Palladium‐Catalyzed Amination

“…In 1998 we introduced a new class of air-stable [1] phosphine ligands based on the dialkylbiaryl phosphine backbone. [2] These phosphines have been used as ligands for gold, [3][4][5][6][7][8][9][10][11] silver, [12] rhodium, [13,14] ruthenium [15][16][17] and copper [18] where they have been shown to impart improvements in reactivity and catalyst stability. It is in reactions catalyzed by palladium, however, that they have had by far the greatest impact including the Sonogashira, [19] Negishi, [20] Hiyama, [21][22][23] Kumada [24] and Suzuki [25][26][27][28][29][30] cross-coupling reactions, Heck reaction, [31][32][33] enolate arylation [34][35][36][37] and allylation, [38] reductive cyclization [39] and etherification, [40][41][42][43] silylation, [44] borylation, [45]…”