The first example of intermolecular hydrophosphination of styrene,2 -vinylpyridine and phenylacetylene with PH 3 catalyzed by bis-(amido) complexes [(Me 3 Si) 2 N] 2 M(NHC) 2 (M = Ca, Yb, Sm) coordinated by NHC ligands is described. The reactions of styrene with PH 3 proceed under mild conditions in quantitative yields to afford only anti-Markovnikov product and allow for the chemoselective synthesis of primary,s econdary and tertiary phosphines. Addition of phenylacetylene to PH 3 regardless the initial molar substrates ratio resultsi nt he exclusive formation of at ertiaryt ris-(Z-styryl)-phosphine. Crucial effect of the Lewis base coordinated to the metal ion in precatalyst on catalytic activity in styrene hydrophosphinationw ith PH 3 was demonstrated. Free NHCs were also found to be able to promote addition of PH 3 to styrene, however they provide much lower reactionr ates comparedt ot he metal complexes.The formation of CÀPb onds by single-step intermolecular hydrophosphination reactions of unsaturated substrates is a promising, atom-efficient route to av ariety of phosphorus-containing compounds. To date, an umber of examples of this transformationh ave been achieved due to acid, [1] base, [2] dtransition, [3] alkaline-earth, [4] andr are-earth metal catalysis. [4a, 5] Radicali nitiation [2a,c, 6] was also reported and is covered in several reviews. [2c, 5e, 7] Despite the progress achieved in this area, a substrate scope of this reactionr emains limited and mainly involves activated olefins and ubiquitousp henyl-and diphenylphosphine. Meanwhile, PH 3 addition to alkenes and alkynes, which is ap rogressive and convenient syntheticr oute to av ariety of primary,s econdary and tertiaryp hosphines, still re-mains poorly explored. Ease of synthesis of PH 3 ,i ts low cost (vs. PhPH 2 )a nd availability make it ac ommercially attractive startingc ompound fort he synthesis of phosphines. Hydrophosphination of multiple CÀCb onds with PH 3 becomes feasible under free radical initiation, [8] acid [1] and superbasic [9] conditions, or UV irradiation. [10] However,t his reaction suffers from a lack of selectivity.T he only example of applying late transition metal complexes for catalytic hydrophosphination of activated substrates (acrylonitrile, [11] ethyl acrylate, [12] formaldehyde [13] ) with PH 3 was published by Pringle and co-workers. No examples of PH 3 addition to non-activated olefins, vinyl arenes and alkynes catalyzed by rare-and alkaline-earth metals complexes have been published so far.M oreover,t he examples of hydrophosphination reactions catalyzed by free carbenes also still remain unknown despite the immense progress in organocatalysis achieved through their use. [14] We found that homoand heterolepticY b II ,S m II and Ca II amido complexes [4a,c, 5b] performing with high catalytic activity in styrene hydrophosphination with Ph 2 PH and PhPH 2 proved to be completely inert in the case of PH 3 .C omplex {LO NO4 }YbN(SiMe 3 ) 2 (1) [4a] was the only exception that enabled transformationo fP H 3...

A series of amido Ca and Yb(II) complexes LM[N(SiMe)](THF) (1Yb, 1-4Ca) coordinated by amidine-amidopyridinate ligands L were synthesized via a transamination reaction between proligands LH and bisamido complexes M[N(SiMe)](THF) (M = Yb, Ca). The reactions of Yb[N(SiMe)](THF) with proligands LH-LH containing CF and CHF fragments do not allow for preparing the target Yb(II) complexes, while the Ca analogues were synthesized in good yields. Complexes 1Yb and 1-4Ca were evaluated as precatalysts for hydrophosphination of styrene, p-substituted styrenes, α-Me-styrene, and 2,3-dimethylbutadiene with various primary and secondary phosphines (PhPH, 2,4,6-MeCHPH, 2-CNHPH, PhPH, CyPH). Complexes 1Yb, 1-4Ca performed high catalytic activities in styrene hydrophosphination with PhPH and PhPH and demonstrated high regioselectivity affording exclusively the anti-Markovnikov addition products. For primary PhPH the reactions (1:1 molar ratio of substrates) catalyzed by 1Yb, 1Ca, and 2Ca proved to be highly chemoselective affording the secondary phosphine Ph(PhCHCH)PH; however, complexes 3Ca and 4Ca led to the formation of both secondary and tertiary phosphines in 80:20 and 86:14 ratios. Styrene hydrophosphinations with 2,4,6-MeCHPH and 2-pyridylphosphine for all complexes 1Yb and 1-4Ca proceeded much more slowly compared to PhPH. Addition of 2-CNHPH to styrene catalyzed by complex 1Yb turned out to be non-regioselective and led to the formation of a mixture of Markovnikov and anti-Markovnikov addition products, while all Ca complexes enabled regioselective anti-Markovnikov addition. Complexes 1Ca and 1Yb containing catalytic centers featuring similar ionic radii performed different catalytic activity: the ytterbium analogue proved to be a more active catalyst for intermolecular hydrophosphination of styrene with CyPH, 2-CNHPH, and PhPH, but less active with sterically demanding 2,4,6-MeCHPH. Styrenes containing in p-position electron-donating groups (Me, tBu, OMe) performed with noticeably lower rates in the reactions with PhPH compared to styrene. Complexes 1Yb, 1Ca, 2Ca, 3Ca, and 4Ca enabled addition of PhPH toward the double C═C bond of α-Me-styrene, and the reaction rate for this substrate is noticeably lower; however quantitative conversions were reached in ∼40 h. Complexes 1Ca and 2Ca promoted 1,2-addition of PhPH to 2,3-dimethyl butadiene with excellent regio- and chemoselectivity to afford linear secondary phosphines. Hydrophosphination of inert 1-nonene with PhPH with 40% conversion becomes possible due to the application of complex 2Ca (40 h, 70 °C). The rate law for the hydrophosphination of styrene with PhPH catalyzed by 1Ca was found to agree with the idealized equation: v = k[styrene][1Ca].

First Ln(ii) ring-expanded NHC complexes (er-NHC)Ln[N(SiMe3)2]2 (Ln = Sm, Yb) are synthesized and proved to be highly efficient pre-catalysts for the intermolecular hydrophosphination of such indolent substrates as 1-alkenes, cyclohexene and norbornene.

A series of NHC-stabilized amido compounds (NHC) n M­[N­(SiMe3)2]2 (M = Yb­(II), Sm­(II), Ca­(II); n = 1, 2) showed remarkable catalytic efficiency in addition of PhPH2 and PH3 to alkenes under mild conditions and low catalyst loading. The effect of σ-donor capacity of NHCs on catalytic activity in hydrophosphination of styrene with PhPH2 and PH3 was revealed. For the series of three-coordinate complexes 1–4M, a tendency to increase the catalytic activity with growth of σ-donating strength of the carbene ligand was clearly demonstrated. The complex (NHC)2Sm­[N­(SiMe3)2]2 (NHC = 1,3-diisopropyl-2H-imidazole-2-ylidene) (5Sm) proved to be the most efficient catalyst, which enabled hardly realizable transformations such as PhPH2 addition across internal CC bonds of norbornene and cis- and trans-stilbenes, providing the highest reaction rate for addition of PH3 to styrene. Excellent regio- and chemoselectivities of alkylation of PH3 with styrenes allow for a selective and good-yield synthesis of desired organophosphineseither primary, secondary, or tertiary. Stepwise alkylation of PH3 with various substituted styrenes can be efficiently applied as an approach to nonsymmetric secondary phosphines. The rate equation of the addition of styrene to PH3 promoted by 5Sm was found: rate = k[styrene]1[5Sm]1.

4,5-Dimethyl-1,3-bis(pyridin-2-ylmethyl)-1H-imidazolium chloride (1) was synthesized and characterized by IR and NMR spectroscopy and X-ray diff raction. An attempt to prepare the free tridentate N-heterocyclic carbene pincer ligand by the reaction of 1 with KN(SiMe 3 ) 2 resulted in the formation of 1,1´-bis(pyridin-2-ylmethyl)-2,2´-bis(4,5-dimethylimidazole) as a product of dimerization of the target carbene followed by the rearrangement accompanied by the elimination of dipyridylethane.

The half-sandwich fluorenyl-amido complex [2,7-tBu 2 -9-SiMe 3 C 13 H 6 ]Yb[N(SiMe 3 ) 2 ](DME) was synthesized by the reaction of [(Me 3 Si) 2 N] 2 Yb(THF) 2 with 2,7-tBu 2 -9-SiMe 3 C 13 H 7 (1:1 molar ratio) in 83% yield. The analogous reaction of [(Me 3 Si) 2 N] 2 Sm(THF) 2 affords a mixture of equimolar amounts of the half-sandwich complexes [2,7-tBu 2 -9-SiMe 3) was synthesized in 60% yield by reacting [(Me 3 Si) 2 N] 2 Sm(THF) 2 with 2 equiv of 2,7-tBu 2 -9-SiMe 3 C 13 H 7 . Complexes 2b and 3 result from competitive abstraction of H or SiMe 3 from 2,7-tBu 2 -9-SiMe 3 -fluorene by an amido group. In contrast, the homoligand sandwich complex [2,7-tBu 2 -9-SiMe 3 C 13 H 6 ] 2 Sm(DME) (5) could be synthesized in 80% yield when [(p-tBuC 6 H 4 ) 2 CH] 2 Sm(DME) 2 was used as a precursor. The complex (2,7-tBu 2 C 13 H 7 ) 2 Sm(THF) 2 (6) was synthesized by the reaction of 2,7-tBu 2 C 13 H 8 with [(Me 3 Si) 2 N] 2 Sm(THF) 2 (2:1) in 65% yields. The crystal structures of complexes 1, 2a,b, 3, 5, and 6 were established by X-ray analyses.

The first example of intermolecular highly regio‐ and chemoselective hydrophosphination of olefins and acetylenes with PH3 catalyzed by CaII, YbII, and SmII bis‐(amido) complexes coordinated by NHC ligands is described. The molecules of styrene, phosphine, and primary, secondary, and tertiary phosphines are symbolically depicted in the form of the puppets driven by a green catalyst controlling the chemoselectivity of the hydrophosphination process. More information can be found in the Communication by A. A. Trifonov et al. on page 459.

The treatment of 4,5-dimethyl-1,3-bis(2-pyridylmethyl)-1H-imidazolium chloride with M[N(SiMe 3 ) 2 ] 2 (THF) 2 (M = Ca, Yb) in 1:2 molar ratio results in the formation of a carbene fragment, activation of the picolyl CH bond, and dearomatization of one of the pyridine rings and affords bis(amido) complexes [(NHC)MN-(SiMe 3 ) 2 ] 2 (M = Ca (2), Yb (3)) coordinated by a μ 2 -bridging pincer NHC amido ligand. Complexes 2 and 3 demonstrate high catalytic activity and excellent regio-and chemoselectivities in the intermolecular hydrophosphination of styrene with both primary and secondary phosphines. Complexes 2 and 3 enable selective addition of PhPH 2 , Ph 2 PH, (CH 2 ) 4 NH, and (CH 2 ) 5 NH to para-divinylbenzene with high conversions under mild conditions. Tandem hydrophosphination/hydroamination of para-divinylbenzene was also performed.