- A versatile method for suzuki cross-coupling reactions of nitrogen heterocycles
-
(Chemical Equation Presented) A wide-ranging study of Suzuki reactions which use nitrogen-containing heterocycles is described (see scheme; dba = dibenzylideneacetone, Cy = cyclohexyl). This method is highly versatile (a single procedure was used for all substrates, including boronate esters and trifluoroborates), compatible with a variety of unprotected functionalities (e.g., NH2-and OH-substituted substrates), and efficient even with unactivated aryl chlorides.
- Kudo, Noriaki,Perseghini, Mauro,Fu, Gregory C.
-
p. 1282 - 1284
(2007/10/03)
-
- Experimental and computational probes of a self-assembled capsule
-
This research was undertaken to explore the interior surface of a synthetic receptor 1.1 with arylpyridines as guests. The interior surface differentiates the guests through the recognition of their nitrogen atoms. Experimental and computational analyses revealed that there is a delicate balance of attractions and repulsions between the host and the lone pairs of guests.
- Iwasawa, Tetsuo,Ajami, Dariush,Rebek Jr., Julius
-
p. 2925 - 2928
(2007/10/03)
-
- Catalysts for Suzuki-Miyaura coupling processes: Scope and studies of the effect of ligand structure
-
Suzuki-Miyaura coupling reactions of aryl and heteroaryl halides with aryl-, heteroaryl- and vinylboronic acids proceed in very good to excellent yield with the use of 2-(2′,6′-dimethoxybiphenyl) dicyclohexylphosphine, SPhos (1). This ligand confers unprecedented activity for these processes, allowing reactions to be performed at low catalyst levels, to prepare extremely hindered biaryls and to be carried out, in general, for reactions of aryl chlorides at room temperature. Additionally, structural studies of various 1·Pd complexes are presented along with computational data that help elucidate the efficacy that 1 imparts on Suzuki-Miyaura coupling processes. Moreover, a comparison of the reactions with 1 and with 2-(2′,4′,6′-triisopropylbiphenyl)diphenylphosphine (2) is presented that is informative in determining the relative importance of ligand bulk and electron-donating ability in the high activity of catalysts derived from ligands of this type. Further, when the aryl bromide becomes too hindered, an interesting C-H bond functionalization-cross-coupling sequence intervenes to provide product in high yield.
- Barder, Timothy E.,Walker, Shawn D.,Martinelli, Joseph R.,Buchwald, Stephen L.
-
p. 4685 - 4696
(2007/10/03)
-
- Efficient catalyst for the Suzuki-Miyaura coupling of potassium aryl trifluoroborates with aryl chlorides
-
Palladium-catalyzed Suzuki-Miyaura cross-coupling reactions of aryl- and heteroaryl chlorides with potassium aryl- and heteroaryltrifluoroborates have been accomplished with the supporting ligand S-Phos in good to excellent yield. Hindered biaryls and substrates containing a variety of functional groups can be prepared. Suzuki-Miyaura couplings of a 3-pyridyl boron-based nucleophile with aryl- and heteroaryl chlorides proceed in good to very good yield.
- Barder, Timothy E.,Buchwald, Stephen L.
-
p. 2649 - 2652
(2007/10/03)
-