ortho,ortho′‐Substituted KITPHOS Monophosphines: Highly Efficient Ligands for Palladium‐Catalyzed CC and CN Bond Formation

Abstract

ortho,ortho'-Substitution of the phos-

A General Palladium–Phosphine Complex To Explore Aryl Tosylates in the N‐Arylation of Amines: Scope and Limitations

“…4‐(2,5‐Dimethylphenyl)morpholine (Table , entry 7): R f =0.5 (hexane/EtOAc=20:1); 1 H NMR (400 MHz, CDCl 3 ): δ =2.36 (t, J= 7.6 Hz, 6 H), 3.2.95 (t, J= 4.4 Hz, 4 H), 3.90 (t, J= 4.4 Hz, 4 H), 6.87 (s, 1 H), 6.89 (s, 1 H), 7.14 ppm (d, J= 7.2 Hz, 1 H); 13 C NMR (100 MHz, CDCl 3 ): δ =17.4, 21.2, 52.3, 67.5, 119.7, 124.0, 129.3, 131.0, 136.2, 151.1 ppm.…”

Gold‐Catalyzed Cyclizations: A Comparative Study of ortho,ortho′‐Substituted KITPHOS Monophosphines with their Biaryl Monophosphine Counterpart SPHOS

“…and 2-(dicyclohexylphosphin-A C H T U N G T R E N N U N G oylethynyl)anisole (9) in 1,2-dichloroethane at 80 8C for 48 h gave 10 in excellent yield, after purification by column chromatography. Reduction of 10 was achieved in good yield by heating a toluene solution containing chlorosilane, triethylamine and the oxide at 110 8C for 48 h to afford biarylmonophosphine 11 (Scheme 1) The identity and purity of 11 has been established using conventional spectroscopic and analytical techniques.…”

“…[9] Since the biaryl architecture of electron-rich monophosphines has also recently been constructed by rhodium-catalyzed [2 + 2 + 2] cycloaddition of tethered diynes with 1-alkynylphosphine oxides and sulfides, [12] we also used this methodology to synthesize a new electron-rich MeO-substituted Buchwald-type monophosphine, 11. Slow addition of a slight excess of 1,7-octadiyne to a solution of …”

“…Encouragingly, our early studies showed that electron-rich KTPHOS monophosphines were highly efficient ligands for palladium-catalyzed C À C and C À N bond formation [8] and that ortho,ortho'-substitution of the proximal aryl ring enhances catalyst performance compared with the corresponding systems based on their unsubstituted or monosubstituted counterparts. [9] Moreover, electron-rich KITPHOS monophosphines either competed with or outperformed their biaryl-based counterparts in palladiumcatalyzed cross-coupling which prompted us to extend our studies to include gold-catalyzed cyclizations. [10] While electrophilic Lewis acid gold(I) triflimide complexes of electron-rich KITPHOS monophosphines were shown to be an efficient catalyst for a range of cycloisomerizations to afford phenols, tetrahydropyrans, lactones and alkylidene-oxazolines, more recent studies have shown that catalysts based on diphenylphosphino-substituted KITPHOS monophosphines outperformed their electron-rich dicyclohexylphosphino counterparts for the cycloisomerization of a range of propargylic amides.…”

Tetraphosphine/palladium‐catalyzed Suzuki–Miyaura coupling of heteroaryl halides with 3‐pyridine‐ and 3‐thiopheneboronic acid: an efficient catalyst for the formation of biheteroaryls

“…Palladium‐catalyzed Suzuki–Miyaura coupling is a powerful and synthetically valuable process for the preparation of heteroaryl derivatives . In recent years, much work has been directed toward the coupling of arylboronic acids with heteroaryl halides, but the reactions involving heteroarylboronic acids with heteroaryl halides are regarded as challenges and have earned less attention …”