Thermolysis of the P-coordinated KITPHOS monophosphine complex [(p-cymene)RuCl2(KITPHOS)] in chlorobenzene at 120 °C resulted in displacement of the p-cymene to afford [{κ(P)-η6-KITPHOS}RuCl2], the first example of a constrained-geometry complex in which the κ(P)-bonded diphenylphosphino group and the η6-coordinated proximal phenyl ring are connected by an unsaturated two-carbon tether; both complexes form efficient catalysts for the direct ortho arylation of 2-phenylpyridine and N-phenylpyrazole with a range of aryl chlorides.

Electrophilic gold(I) complexes of diphenyl-and dicyclohexylphosphino-based KITPHOS monophosphines catalyze the 5-exo-dig cycloisomerization of a range of propargyl amides to afford the corresponding alkylidene oxazolines; in all cases catalysts formed from diphenylphosphino-substituted KITPHOS monophosphines outperformed their dicyclohexylphosphino counterparts as well as that based on triphenylphosphine, an indication that the biaryl/biaryl-like framework may be responsible for imparting high catalyst efficiency.

A comparative study of the carbonyl-ene reaction between a range of 1,1'-disubstituted or trisubstituted alkenes and ethyl trifluoropyruvate catalyzed by Lewis acid-platinum group metal complexes of the type [M{(R)-BINAP}]2+ (M = Pt, Pd, Ni; BINAP is 2,2'-bis(diphenylphosphino)-1,1'-binaphthyl) revealed subtle but significant differences in their reactivity. For instance, the palladium-based Lewis acid [Pd{(R)-BINAP}]2+ catalyzes the ene reaction between methylene cycloalkane to afford the expected alpha-hydroxy ester in good yield and excellent diastereo- and enantioselectivity. In contrast, under the same conditions, the corresponding [M{(R)-BINAP}]2+ (M = Pt, Ni) catalyzes isomerization of methylene cycloalkane and the ene reaction of the resulting mixture of methylene cycloalkane and 1-methylcycloalkene at similar rates to afford a range of -hydroxy esters in high regioselectivity, good diastereoselectivity, and good to excellent enantioselectivity. In addition, [Pt{(R)-BINAP}]2+ also catalyzes postreaction isomerization of the ene product as well as consecutive ene reactions to afford a double carbonyl-ene product. The sense of asymmetric induction has been established by single-crystal X-ray crystallography, and a stereochemical model consistent with the formation of (S)-configured -hydroxy ester has been proposed; the same model also accounts for the observed exo-diastereoselectivity as well as the level of diastereoselectivity.

Rhodium-catalyzed double [2 + 2 + 2] cycloaddition of 1,4-bis(diphenylphosphinoyl)buta-1,3-diyne with tethered diynes provides a straightforward, single-pot procedure for the synthesis of a new class of tropos biaryl diphosphine, NU-BIPHEP. This methodology represents a significant improvement on existing multistep procedures. Enantiopure Lewis acid platinum complexes of these diphosphines are highly efficient catalysts for carbonyl-ene and Diels-Alder reactions, and ruthenium diphosphine-diamine complexes catalyze the asymmetric reduction of ketones to give ee's that rival those obtained with their BINAP counterpart.

Electron-rich, bicyclic biaryl-like KIT-PHOS monophosphines have been prepared via Diels-Alder cycloaddition between 1-alkynylphosphine oxides and anthracene in an operationally straightforward and highly modular synthetic protocol that will allow access to an architecturally and electronically diverse family of ligands. Palladium complexes of these ligands are highly efficient catalysts for the Buchwald-Hartwig amination and Suzuki-Miyaura coupling of a wide range of aryl chlorides, which for the vast majority of substrate combinations outperform their o-(dicyclohexylphosphino)biphenyl-based counterparts.

This protocol describes the synthesis of a representative example of the electron-rich biaryl-like KITPHOS class of monophosphine, 11-dicyclohexylphosphino-12-phenyl-9,10-dihydro-9,10-ethenoanthracene (H-KITPHOS). The bicyclic architecture of H-KITPHOS is constructed via [4+2] Diels-Alder cycloaddition between 1-(dicyclohexylphosphinoylethynyl)benzene and anthracene. H-KITPHOS monophosphine is prepared via an operationally straightforward three-step procedure and is isolated in an overall yield of ∼55%. The synthesis of palladium and gold precatalysts of H-KITPHOS are also described; the yields of analytically pure complexes are high (75-85% and 85-90%, respectively). The palladium complex of H-KITPHOS forms a highly active catalyst for C-C and C-N cross-coupling of a range of aryl and heteroaryl chlorides and bromides, and the electrophilic Lewis acid gold complex efficiently catalyzes a host of cycloisomerizations. The total time required for the synthesis of H-KITPHOS is 95 h; the preparation of corresponding palladium and gold precatalysts requires an additional 7-8 h, and, if necessary, crystallizations will require a further 48 h.

S11-12Table S1. Crystallographic data for compounds 3a and 4 General Comments. All manipulations involving air-sensitive materials were carried out using standard Schlenk line techniques under an atmosphere of nitrogen or argon in oven-dried glassware.Dichloromethane, 1,2-dichloroethane and chlorobenzene were distilled from calcium hydride. 1,7-octadiyne, ethyl trifluoropyruvate, allylbenzene, silver hexafluoroantimonate, rac-and (R)-BINAP were purchased from commercial suppliers and used without further purification. [RhCl(COD)] 2 , 1 [(cycloocta-1,5-diene)PtCl 2 ], 2 2,8-decadiyne, 3 2,2-di(prop-2-ynyl)malonic acid dimethyl ester 4 2,2-di(but-2-ynyl)malonic acid dimethyl ester 5 and 1,4-bis(diphenylphosphino)buta-1,3-diyne 6 were prepared as previously described. 1 H and 13 C{ 1 H} NMR spectra were recorded on a JEOL LAMBDA 500 or a Bruker AMX 300 instrument. Optical rotations were measured on a Optical Activity PolAAr 2001 digital polarimeter with a sodium lamp and are reported as follows: [ ] D 20 (c g/100 mL, solvent). Thin-layer chromatography (TLC) was carried out on aluminum sheets pre-coated with silica gel 60F 254 and column chromatography was performed using Merck Kieselgel 60. Gas chromatography was performed on a Shimadzu 2010 series gas chromatograph equipped with a split-mode capillary injection system and flame ionization detection using a Supelco Beta DEX column.Analytical high performance liquid chromatography (HPLC) was performed on an Agilent 110 Series HPLC equipped with a variable wavelength detector using a Daicel Chiralcel OD-H or AD-H column. Enantiomeric excesses were calculated from the HPLC and GC profiles. Synthesis of Cycloadduct 3a.A flame-dried Schlenk flask was charged with [RhCl(COD)] 2 (0.027 mg, 0.05 mmol), AgSbF 6 (0.038 g, 0.11 mmol), rac-BINAP (0.069 g, 0.11 mmol) and 1,2-dichloroethane (20 mL).1,4-Bis(diphenylphosphinoyl)buta-1,3-diyne (0.500 g, 1.11 mmol) and 2,2-di(but-2-ynyl)malonic acid dimethyl ester (0.315 g, 1.33 mmol) were added and the resulting solution stirred at 80 °C for 3-4 hr. After this time, the solvent was removed in vacuo to leave a crude brown solid which was purified by column chromatography eluting with ethyl acetate/acetone (4:1) to yield the product as a beige solid (0.702 g, 92%).

Lewis acid complexes of the type [M{(R)-BINAP}][SbF 6 ] 2 (M ) Pt, Pd, Ni) catalyze the reaction between R-methylstyrenes and ethyl trifluoropyruvate to afford products resulting from the expected carbonyl-ene reactivity as well as tandem alkene dimerization-carbonyl-ene addition and alkene dimerization-Friedel-Crafts alkylation pathways, the distribution of which depends on the metal and the substituent attached to the aromatic ring of the styrene substrate. Kinetic studies reveal that the Lewis acid platinum complex catalyzes the dimerization of 4-chloro-R-methylstyrene much faster than its palladium counterpart and that the corresponding nickel system has platinum-like reactivity and selectivity.