1088-00-2Relevant academic research and scientific papers
Bridged [2.2.1] bicyclic phosphine oxide facilitates catalytic γ-umpolung addition-Wittig olefination
Zhang, Kui,Cai, Lingchao,Yang, Zhongyue,Houk,Kwon, Ohyun
, p. 1867 - 1872 (2018)
A novel bridged [2.2.1] bicyclic phosphine oxide, devised to circumvent the waste generation and burdens of purification that are typical of reactions driven by the generation of phosphine oxides, has been prepared in three steps from commercially availab
Study of the reaction of bulky aryllithium reagents with 3,4-dimethyl-2,5-diphenyl-1,3,2-oxazaphospholidine-2-borane derived from ephedrine
Stephan, Michel,Sterk, Damjan,Modec, Barbara,Mohar, Barbara
, p. 8010 - 8018 (2007)
(Chemical Equation Presented) The ring opening of enantiomerically pure 3,4-dimethyl-2,5-diphenyl-1,3,2-oxazaphospholidine-2-borane (1) with a variety of bulky aryllithium reagents was studied. Our results are not in total agreement with those obtained by
Phosphorescent OLEDs assembled using Os(ii) phosphors and a bipolar host material consisting of both carbazole and dibenzophosphole oxide
Lin, Cheng-Huei,Hsu, Che-Wei,Liao, Jia-Ling,Cheng, Yi-Ming,Chi, Yun,Lin, Tsung-Yi,Chung, Min-Wen,Chou, Pi-Tai,Lee, Gene-Hsiang,Chang, Chih-Hao,Shih, Chin-Yao,Ho, Chi-Lung
, p. 10684 - 10694 (2012)
We report on the synthesis of a new series of Os(ii) complexes (1-3) functionalized with 2-pyridyl (or 2-isoquinolyl) pyrazole chelates, together with a new diphosphine, 1,2-bis(phospholano)benzene chelate (pp2b). The resulting Os(ii) complexes are fully characterized and their structural versus spectroscopic properties have been comprehended by absorption/emission together with computational approaches. The inherent electron richness, restricted rotational barrier and good steric hindrance of pp2b lead to the production of both orange and red phosphorescence with high quantum efficiency. For exploring these Os(ii) based OLEDs, we also synthesized a bipolar material 5-[4-(carbazo-9-yl)phenyl] dibenzophosphole-5-oxide (CzPhO), possessing both carbazole donor and dibenzophosphole oxide acceptor. Successful fabrication of OLEDs using complexes 1 and 3 as the dopant and either 4,4′-N,N′- dicarbazolebiphenyl (CBP) or CzPhO as host is reported. For comparison, the CBP and CzPhO devices with 1 as the emitter showed peak efficiencies EQE of 10.9%, ηL of 21.7 cd A-1, and ηp of 11.9 lm W-1, and EQE of 14.3%, ηL of 34.8 cd A-1, and ηp of 45.2 lm W-1, respectively. The Royal Society of Chemistry 2012.
2,2′-Bis(diphenylphosphino)biphenyl revisited
Desponds, Olivier,Schlosser, Manfred
, p. 257 - 261 (1996)
The reaction between 2,2′-dilithiobiphenyl and two equivalents of chlorodiphenylphosphine is confirmed to afford equal amounts of 9-phenyl-9-phosphafluorene (2) and triphenylphosphine. 2,2′-Bis(diphenylphosphino)biphenyl (1,1′-biphenyl-2,2′-diylbis(diphenylphosphine) (1)) can be conveniently prepared by Ullmann coupling of 2-iodophenyldiphenylphosphine oxide and subsequent reduction with trichlorosilane.
Biphilic Organophosphorus-Catalyzed Intramolecular Csp2-H Amination: Evidence for a Nitrenoid in Catalytic Cadogan Cyclizations
Nykaza, Trevor V.,Ramirez, Antonio,Harrison, Tyler S.,Luzung, Michael R.,Radosevich, Alexander T.
supporting information, p. 3103 - 3113 (2018/03/08)
A small-ring phosphacycloalkane (1,2,2,3,4,4-hexamethylphosphetane, 3) catalyzes intramolecular C-N bond forming heterocyclization of o-nitrobiaryl and -styrenyl derivatives in the presence of a hydrosilane terminal reductant. The method provides scalable access to diverse carbazole and indole compounds under operationally trivial homogeneous organocatalytic conditions, as demonstrated by 17 examples conducted on 1 g scale. In situ NMR reaction monitoring studies support a mechanism involving catalytic PIII/PV=O cycling, where tricoordinate phosphorus compound 3 represents the catalytic resting state. For the catalytic conversion of o-nitrobiphenyl to carbazole, the kinetic reaction order was determined for phosphetane catalyst 3 (first order), substrate (first order), and phenylsilane (zeroth order). For differentially 5-substituted 2-nitrobiphenyls, the transformation is accelerated by electron-withdrawing substituents (Hammett factor ? = +1.5), consistent with the accrual of negative charge on the nitro substrate in the rate-determining step. DFT modeling of the turnover-limiting deoxygenation event implicates a rate-determining (3 + 1) cheletropic addition between the phosphetane catalyst 3 and 2-nitrobiphenyl substrate to form an unobserved pentacoordinate spiro-bicyclic dioxazaphosphetane, which decomposes via (2 + 2) cycloreversion giving 1 equiv of phosphetane P-oxide 3·[O] and 2-nitrosobiphenyl. Experimental and computational investigations into the C-N bond forming event suggest the involvement of an oxazaphosphirane (2 + 1) adduct between 3 and 2-nitrosobiphenyl, which evolves through loss of phosphetane P-oxide 3·[O] to give the observed carbazole product via C-H insertion in a nitrene-like fashion.
Intermolecular Reductive C-N Cross Coupling of Nitroarenes and Boronic Acids by PIII/PV=O Catalysis
Nykaza, Trevor V.,Cooper, Julian C.,Li, Gen,Mahieu, Nolwenn,Ramirez, Antonio,Luzung, Michael R.,Radosevich, Alexander T.
supporting information, p. 15200 - 15205 (2018/11/30)
A main group-catalyzed method for the synthesis of aryl- and heteroarylamines by intermolecular C-N coupling is reported. The method employs a small-ring organophosphorus-based catalyst (1,2,2,3,4,4-hexamethylphosphetane) and a terminal hydrosilane reductant (phenylsilane) to drive reductive intermolecular coupling of nitro(hetero)arenes with boronic acids. Applications to the construction of both Csp2-N (from arylboronic acids) and Csp3-N bonds (from alkylboronic acids) are demonstrated; the reaction is stereospecific with respect to Csp3-N bond formation. The method constitutes a new route from readily available building blocks to valuable nitrogen-containing products with complementarity in both scope and chemoselectivity to existing catalytic C-N coupling methods.
Mitsunobu Reactions Catalytic in Phosphine and a Fully Catalytic System
Buonomo, Joseph A.,Aldrich, Courtney C.
supporting information, p. 13041 - 13044 (2015/11/02)
The Mitsunobu reaction is renowned for its mild reaction conditions and broad substrate tolerance, but has limited utility in process chemistry and industrial applications due to poor atom economy and the generation of stoichiometric phosphine oxide and hydrazine by-products that complicate purification. A catalytic Mitsunobu reaction using innocuous reagents to recycle these by-products would overcome both of these shortcomings. Herein we report a protocol that is catalytic in phosphine (1-phenylphospholane) employing phenylsilane to recycle the catalyst. Integration of this phosphine catalytic cycle with Taniguchi's azocarboxylate catalytic system provided the first fully catalytic Mitsunobu reaction. Make it catalytic: A catalytic Mitsunobu reaction using innocuous reagents to recycle the stoichiometric phosphine oxide and hydrazine by-products was developed. The reported method is catalytic in 1-phenylphospholane and uses phenylsilane to recycle the catalyst. Integration of this phosphine catalytic cycle with Taniguchi's azocarboxylate catalytic system provided the first fully catalytic Mitsunobu reaction.
Palladium-Catalyzed Synthesis of Six-Membered Benzofuzed Phosphacycles via Carbon-Phosphorus Bond Cleavage
Baba, Katsuaki,Tobisu, Mamoru,Chatani, Naoto
, p. 70 - 73 (2015/07/28)
The palladium-catalyzed synthesis of dibenzofused six-membered phosphacycles via carbon-phosphorus bond cleavage is developed. This method is compatible with a range of functional groups, such as esters, amides, and carbamates, which is in sharp contrast to the limitations of the classical method using organolithium reagents. (Figure Presented).
First ever observation of the intermediate of phosphonium salt and ylide hydrolysis: P-hydroxytetraorganophosphorane
Byrne, Peter A.,Ortin, Yannick,Gilheany, Declan G.
supporting information, p. 1147 - 1150 (2015/02/19)
P-Hydroxytetraorganophosphorane, the long-postulated intermediate in phosphonium salt and ylide hydrolysis, has been observed and characterised by low temperature NMR, finally definitively establishing its involvement in these reactions. The results require modification of the previously accepted mechanism for ylide hydrolysis: P-hydroxytetraorganophosphorane is generated directly by 4-centre reaction of ylide with water. This journal is
Synthesis of annelated phospholes through intramolecular C-H activation by monovalent phosphorus
Wei, Xinda,Lu, Zongming,Zhao, Xu,Duan, Zheng,Mathey, Francois
supporting information, p. 1583 - 1586 (2015/01/30)
Electrophilic terminal phosphinidene complexes [Ar-Ar-P-W(CO)5] (Ar-Ar: biaryl or an analogue thereof) undergo a spontaneous insertion of the phosphorus atom into the vicinal C-H bonds to give annelated phospholes. Twelve examples are described, including biphenyl, thienyl, pyrrolyl, and benzofuryl groups as biaryl moieties. The activation energy of the insertion reaction is quite low (about 2 kcal mol-1).
