Phosphine boran

We previously revealed that phosphine-boranes can function as molecular frameworks for biofunctional molecules. In the present study, we exploited the diversity of available phosphines to design and synthesize a series of B -(trifluoromethyl)phenyl phosphine-borane derivatives as novel progesterone receptor (PR) antagonists. We revealed that the synthesized phosphine-borane derivatives exhibited Log P values in a predictable manner and that the P-H group in the phosphine-borane was almost nonpolar. Among the synthesized phosphine-boranes, which exhibited PR antagonistic activity, B -(4-trifluoromethyl)phenyl tricyclopropylphosphine-borane was the most potent with an IC50 value of 0...

Phosphine-boranes do not promote oxidative addition of acyl chlorides to gold, but the phosphine-borane gold triflimide complex [i Pr2 P( o -C6 H4 )BCy2 ]AuNTf2 was found to catalyze the coupling of acyl chlorides and aryl stannanes. The reaction involves aryl/chloride-bridged dinuclear gold(i) complexes as key intermediates, as substantiated by spectroscopic and crystallographic analyses. Similar to Pd(0)/Pd(ii)-catalyzed Stille coupling with phosphine-borane ligands, the gold-catalyzed variant shows complete chemoselectivity for acyl chlorides over aryl iodides and bromides, enabling straightforward access to halogenated aryl ketones...

Described herein is the successful crystallization-induced dynamic resolution (CIDR) of an α-lithiated phosphine borane utilizing the easily accessible and inexpensive ligand (R,R)-TMCDA. Starting from the essential P-prochiral building block dimethyl phenyl phosphine borane we were able to obtain phosphine boranes in yields up to 80% and e.r. up to 98:2 by crystallization of the lithiated intermediate prior to the trapping reaction. NMR-based deuterium labeling experiments indicate that the epimerization in solution is based on the intermolecular proton transfer between nonlithiated phosphine borane and the corresponding lithiated intermediate, rendering the presence of the remaining starting compound in an optimized solvent mixture the main factor for successful enantioselective synthesis...

The synthesis and characterization of a bis-iron(II) complex was accomplished upon treatment of a phosphine free NNN-pincer ligand (L) with FeCl2 ·4H2 O under ambient conditions. The deep greenish colored iron(II) complex (Fe-1) was characterized by a single-crystal X-ray diffraction study along with IR spectroscopy, UV-Vis spectroscopy, mass spectrometry, and elemental analysis. The Fe-1 complex was tested for the transfer semi-hydrogenation of terminal alkynes to the corresponding alkenes through the dehydrogenation of dimethyl amine-borane...

Increasing the structural options in medicinal chemistry is a promising approach to develop new drug candidates. In this research, we designed and synthesized a series of B -hydroxyphenyl phosphine borane derivatives and investigated their structure-property and structure-activity relationships. The synthesized B -phenylphosphine borane derivatives exhibited sufficient stability in aqueous media, weaker hydrophobicity than the corresponding alkanes and silanes, and sufficient affinity for lipid membranes to enable permeability...

In the recent past, the chirality borne by a phosphorus center has aroused growing interest in many fields, and the development of new methodologies, notably using inexpensive reagents and simple experimental conditions, has become topical. An efficient stereoselective synthesis of P-chirogenic phosphinites useful as chiral phosphorus building blocks is herein described thanks to a new intramolecular phosphorus rearrangement based on P*(III)-phosphinyl N→O migration. This rearrangement was performed by heating at 50 °C aminophosphine-boranes, easily prepared from chiral amino alcohols, with DABCO in toluene overnight...

Phosphine periodic mesoporous organosilicas (R-P-PMO-TMS: R = Ph, tBu), which possess electron-donating alkyl substituents on the phosphorus atom, were synthesized using bifunctional compounds with alkoxysilyl- and phosphino groups, bis[3-(triethoxysilyl)propyl]phenylphosphine borane (1a) and bis[3-(triethoxysilyl)propyl]-tert-butylphosphine borane (1b). Immobilization of Pd(0) species was performed to give R-P-Pd-PMO-TMS: R = Ph (2a), tBu (3a), respectively. The Pd(0) immobilized 2a and 3a were applicable as catalysts for Suzuki-Miyaura cross-coupling reactions of aryl chlorides with phenylboronic acid...

In an effort to establish B-P coupling reactions without the use of phosphine-borane dehydrocoupling agent, we have developed a new synthetic methodology employing group 8 metal σ-borate complex [{κ3-H,S,S'-BH2L2}Ru{κ3-H,H,S-BH3L}] (L = NC5H4S), 1. Treatment of 1 with chlorodiphenyl phosphine (PPh2Cl) yielded 1,5-P,S chelated Ru-dihydridoborate species [PPh2H{κ3-H,H,S-BH(OH)L}Ru{κ2-P,S-(Ph2P)BH2L}], 2. The insertion of phosphine moiety (PPh2) by the cleavage of 3c-2e σ(Ru…H-B) bonding interaction led to the formation of B-P bond...

While the dimerization of heavier group 13 carbene analogues to the corresponding alkene analogues is known and relatively well understood, the dimerization of dicoordinate borylenes (LRB:, L = neutral donor; R = anionic substituent) to the corresponding diborenes (LRB═BRL) has never been directly observed. In this study we present the first example of a formal borylene-to-diborene dimerization through abstraction of a labile phosphine ligand from the tricoordinate hydroborylene precursor (CAAC)(Me3 P)BH (CAAC = cyclic alkyl(amino)carbene) by bulky Lewis-acidic dihaloboranes (BX2 Y, X = Cl, Br, Y = aryl, boryl), generating the corresponding dihydrodiborene (CAAC)HB═BH(CAAC) and (Me3 P)BX2 Y as the byproduct...

Catalytic asymmetric methods for the synthesis of synthetically versatile P-stereogenic building blocks offer an efficient and practical approach for the diversity-oriented preparation of P-chiral phosphorus compounds. Herein, we report the first nickel-catalyzed synthesis of P-stereogenic secondary aminophosphine-boranes by the asymmetric addition of primary phosphines to azo compounds. We further demonstrate that the P-H and P-N bonds on these phosphanyl hydrazine building blocks can be reacted sequentially and stereospecifically to access various P-stereogenic compounds with structural diversity...

Diimino-carbene-supported germylone dimNHCGe does not react with BPh3 and does not activate dihydrogen in the FLP mode in the combination with this borane. However, it reacts with B(C6F5)3 to give the zwitterionic borate dimNHCGe-(C6F4)BF(C6F5)2. This compound can be converted into the hydroborate dimNHCGe-(C6F4)BH(C6F5)2 (8) and further into [dimNHCGe-(C6F4)B(C6F5)2]+ (4). Compound 4 is a Ge/B analogue of Stephan's FLP parent P/B compound (C6H2Me3)2P-C6F4-B(C6F5)2 but unlike the latter cannot split dihydrogen...

Formation of borabicyclo[3.2.0]heptadiene derivatives was achieved via boron-insertion into aromatic C-C bonds in the photo-promoted skeletal rearrangement reaction of triarylboranes bearing an ortho-phosphino substituent (ambiphilic phosphine-boranes). The borabicyclo[3.2.0]heptadiene derivatives were fully characterized by NMR and X-ray analyses. The dearomatized products were demonstrated to undergo the reverse reaction in the dark at room temperature, realizing photochemical and thermal interconversion between triarylboranes and boron-doped bicyclic systems...

A series of peri -substituted acenaphthene-based phosphine selenoether bidentate ligands Acenap( i Pr2 P)(SeAr) ( L1 - L4 , Acenap = acenaphthene-5,6-diyl, Ar = Ph, mesityl, 2,4,6-trisopropylphenyl and supermesityl) were prepared. The rigid acenaphthene framework induces a forced overlap of the phosphine and selenoether lone pairs, resulting in a large magnitude of through-space 4 J PSe coupling, ranging from 452 to 545 Hz. These rigid ligands L1 - L4 were used to prepare a series of selected late d-block metals, mercury, and borane complexes, which were characterized, including by multinuclear NMR and single-crystal X-ray diffraction...

The access to P-stereogenic motifs has always been considered a very challenging and high attractive mission in modern organic synthesis. While several chiral auxiliaries employed by the practical Jugé-Stephan-like methodology have been developed, new type of readily accessible bifunctional ligands toward P-stereogenic building still remain much desirable. Herein, we present a powerful chiral template, camphor-derived 2,3-diols named CAMDOL, which were designed and synthesized from the commercially cheap camphorquinone in high yields at 50 grams scale with a column-free purification...

The phosphine-borane i Pr2 P( o -C6 H4 )BFxyl2 (Fxyl = 3,5-(F3 C)2 C6 H3 ) 1-Fxyl was found to promote the reductive elimination of ethane from [AuMe2 (μ-Cl)]2 . Nuclear magnetic resonance monitoring revealed the intermediate formation of the ( 1-Fxyl )AuMe2 Cl complex. Density functional theory calculations identified a zwitterionic path as the lowest energy profile, with an overall activation barrier more than 10 kcal/mol lower than without borane assistance. The Lewis acid moiety first abstracts the chloride to generate a zwitterionic Au(III) complex, which then readily undergoes C(sp3 )-C(sp3 ) coupling...

Photoinduced metal-organic framework (MOF) enabled heterogeneous thiol catalysis has been achieved for the first time. MOF Zr-TPDCS-1, consisting of Zr6-clusters and TPDCS linkers (TPDCS = 3,3'',5,5''-tetramercapto[1,1':4',1''-terphenyl]-4,4''-dicarboxylate), effectively catalyzed the borylation, silylation, phosphorylation, and thiolation of organic molecules. Upon irradiation, the fast electron transfer from TPDCS to Zr6-cluster is believed to facilitate the formation of the thiyl radical, a hydrogen atom transfer catalyst, which competently abstracts the hydrogen from borane, silane, phosphine, or thiol for generating the corresponding element radical to engender the chemical transformations...

Interest in main group chemistry related to the Haber-Bosch process has drawn less attention than that of transition metal species. Herein, we show that the steric demands in ( t BuO2 CN)2 block initial interaction of B(C6 F5 )3 with nitrogen and prompt loss of methylpropene and CO2 to diazene (N2 H2 ) borane adduct 1 and the analogous hydrazine (N2 H4 ) adduct 2 . These species react with basic phosphines to give anions of 3 and 5 containing N2 H and N2 H3 fragments, respectively. While these species are not derived directly from N2 , they represent metal-free species containing N2 H n ( n = 1-4) fragments, which model plausible intermediates in the reduction of N2 ...

A novel method for the formation of Csp3-P(III) bonds via the nickel-catalyzed cross-coupling between Umpolung carbonyls and phosphine chlorides is reported herein, leading to a series of alkylphosphines, which are characterized as sulfides or borane-phosphine complexes in moderate to good yields after further transformation. Invaluable free alkylphosphines can be easily obtained by desulfurization or deboration of products. A possible mechanistic pathway is also discussed. This report represents the first example of using renewable carbonyls as latent organometallic reagent surrogates forcross-coupling with heteroatom electrophiles...

Reduction of (NP)PCl2 (NP = phosphinoamidinate [PhC(NAr)(=NPPri2)]-) with KC8 affords the phosphinoamidinato-supported phosphinidene (NP)P (9). Reaction of 9 with a N-heterocyclic carbene (MeC(NMe))2C: results in the NHC-adduct NHC→P-P(Pri2)=NC(Ph)=NAr featuring an iminophosphinyl group. Reactions of 9 with HBpin and H3SiPh led to the metathesis products (NP)Bpin and (NP)SiH2Ph, respectively, whereas with HPPh2 a base-stabilized phosphido-phosphinidene, the product of N-P and H-P bond metathesis, was obtained...

A photoinduced copper-catalyzed C(sp3 )-P bond formation has been developed by using N-(acyloxy)phthalimides as radical precursors and secondary phosphine boranes as coupling partners. A variety of alkyl carboxylic acid derivatives can be readily transformed into the corresponding phosphines with high reaction efficiency and structural diversity. Besides, utilizing the 1,5-HAT of the N-centered radical process, the δ C(sp3 )-H bond can be coupled with secondary phosphines, which provides a novel method for the regioselective formation of C(sp3 )-P bonds...