Synthese und Struktur hochfunktionalisierter 2, 3‐Dihydro‐1H‐1, 3, 2‐diazaborole

Synthesis and Structure of Highly Functionalized 2, 3‐Dihydro‐1H‐1, 3, 2‐diazaboroles A series of differently substituted 2, 3‐dihydro‐1H‐1, 3, 2‐diazaboroles has been prepared by various methods. 1, 3‐Di‐tert‐butyl‐2‐trimethylsilylmethyl‐1H‐1, 3, 2‐diazaborole ( 7 ), 2‐isobutyl‐1, 3‐bis(1‐cyclohexylethyl)‐1H‐1, 3, 2‐diazaborole ( 8 ), 1, 3‐bis‐(1‐cyclohexylethyl)‐2‐trimethylsilylmethyl‐1H‐1, 3, 2‐diazaborole ( 9 ) 1, 3‐bis(1‐methyl‐1‐phenyl‐propyl)‐2‐trimethylsilylmethyl‐1H‐1, 3, 2diazaborole ( 10 ) and 2‐bromo‐1, 3‐bis(1‐methyl‐1‐phenyl‐propyl)‐1H‐1, 3, 2‐diazaborole ( 11 ) were formed by reaction of the corresponding 1, 4‐diazabutadienes with the boranes Me₃SiCH₂BBr₂, iBuBBr₂ and BBr₃ followed by reduction of the resulting borolium salts [R¹ = tBu, Me(cHex)CH, [Me(Et)Ph]C; R² = Me₃SiCH₂, iBu, Br] with sodium amalgam. Treatment of 11 and 12 with silver cyanide afforded the 2‐cyano‐1, 3, 2‐diazaboroles 13 and 14 . An alternative route to compound 8 is based on the alkylation of 2‐bromo‐1, 3, 2‐diazaborole 12 with isobutyllithium. Equimolar amounts of 13 and isobutyllithium give rise to the formation of 15 . The new compounds were characterized by ¹H‐, ¹³C‐, ¹¹B‐NMR, IR and mass spectra. The molecular structures of 7 and meso ‐10 were confirmed by x‐ray structural analysis.     

Chirale 1,3,2‐Oxazaborolidine aus chiralen 2,3‐Dihydro‐1H‐1,3,2‐diazaborolen und Diphenylketen

Chiral 1,3,2‐Oxazaborolidines from the Reaction of Chiral 2,3‐Dihydro‐1H‐1,3,2‐diazaboroles and Diphenylketene Reaction of equimolar amounts of diphenylketene with 1,3‐di‐tert‐butyl‐2‐isobutyl‐2,3‐dihydro‐1H‐1,3,2‐diazaborole ( 1 ) regioselectively afforded 1,3,2‐oxazaborolidine ( 2 ). The employment of a series of chiral diazaboroles ( 3a : X = nBu; b: iBu; c: CH₂SiMe₃; d: NHtBu) led to the formation of the diastereoisomeric oxazaborolidines ( 4a – d ) with diastereomeric excesses de, which increase with the steric demand of X from de = 55 % (X = nBu) to de ≥ 95 % (X = NHtBu). Under comparable conditions the treatment of the enantiomerically pure diazaborole ( 6 ) with the ketene yielded oxazaborolidine ( 7 ) with a de‐value of only 52 %. The new compounds, with exception of 2 and 4d , are thermolabile solids, which were characterized mainly by spectroscopy (¹H‐, ¹¹B{¹H}‐, ¹³C{¹H}‐NMR, MS). The X‐ray structure analysis of 2 revealed a slightly puckered five‐membered heterocycle with a long B–O bond.     

Synthese und Molekülstruktur chiraler Bis(1,3,2‐dioxaphospholane)

Synthesis and Molecular Structure of Chiral Bis(1,3,2‐dioxaphospholanes) Bisphosphites of the general type C₂O₂POC_nOPO₂C₂ containing chiral building blocks both in the five‐membered C₂O₂P rings and in the OC_nO bridge were prepared from 2‐chloro‐1,3,2‐dioxaphospholanes and chiral diols in the presence of a base. The molecular structure of compound 10 , which was obtained from 2‐chloro‐(4R,5R)‐4,5‐dimethyl‐1,3,2‐dioxaphospholane and (R)‐1,1′‐binaphthalin‐2,2′‐diol, was determined by X‐ray crystallography.     

Syntheses,Structure, Electrochemistry,and Optical Properties of 1,3‐Diethyl‐2,3‐dihydro‐1‐H‐1,3,2‐pyrido‐[4,5‐b]‐diazaboroles

Reaction of 2,5‐bis(dibromoboryl)thiophene ( 4 ) or 1,4‐bis(dibromoboryl)benzene ( 6 ) with two equivalents of N,N′‐dilithiated 2,3‐diaminopyridine ( 3 ) led to the generation of the pyridodiazaboroles 5 and 7 in which the two diazaborole rings are linked by 2,5‐thiophen‐diyl or 1,4‐phenylene units via the boron atom. The novel compounds were characterized by elemental analyses and spectroscopy (¹H‐, ¹¹B‐, ¹³C‐NMR, MS, and UV‐VIS). The molecular structure of 5 was elucidated by X‐ray diffraction. Cyclovoltammograms of 5 and 7 show two irreversible oxidation waves at 0.76 and 0.73 V, respectively vs Fc/Fc⁺. The novel compounds display intense blue luminescence with Stokes shifts of 76 and 74 nm and relative quantum yields of 39 and 43 % vs Coumarin 120 (Φ = 50 %).     

Synthese,Struktur, Elektrochemie und optische Eigenschaften von alkinylfunktionalisierten 1,3,2‐Diazaborolen und 1,3,2‐Diazaborolidinen

Syntheses, Structures, Electrochemistry and Optical Properties of Alkyne‐Functionalized 1,3,2‐Diazaboroles and 1,3,2‐Diazaborolidenes The reaction of 2‐bromo‐1,3‐ditert‐butyl‐2,3‐dihydro‐1H‐1,3,2‐diazaborole ( 3 ) with lithiated tert‐butyl‐acetylene and lithiated phenylacetylene affords the 2‐alkynyl‐functionalized 1,3,2‐diazaboroles 4 and 5 as a thermolabile colorless oil ( 4 ) or a solid ( 5 ). Similarly 2‐bromo‐1,3‐diethyl‐2,3‐dihydro‐1H‐1,3,2‐benzodiazaborole ( 6 ) was converted into the crystalline 2‐alkynyl‐benzo‐1,3,2‐diazaboroles 7 and 8 by treatment with LiC≡C–tBu or LiC≡CPh, respectively. 2‐Ethynyl‐1,3‐ditert‐butyl‐2,3‐dihydro‐1H‐1,3,2‐diazaborole ( 2 ) was metalated with tert‐butyl‐lithium and subsequently coupled with 2‐bromo‐1,3,‐ditert‐butyl‐2,3‐dihydro‐1H‐1,3,2‐diazaborole ( 3 ) to afford bis(1,3‐ditert‐butyl‐2,3‐dihydro‐1H‐1,3,2‐diazaborol‐2‐yl)acetylene ( 9 ) as thermolabile colorless crystals. Analogously coupling of the lithiated species with 6 or with 2‐bromo‐1,3‐ditert‐butyl‐1,3,2‐diazaborolidine ( 11 ) gave the unsymmetrically substituted acetylenes 10 or 12 , respectively, as colorless solids. Compounds 4 , 5 , 7 – 10 and 12 are characterized by elemental analyses and spectroscopy (IR, ¹H‐, ¹¹B{¹H}, ¹³C{¹H}‐NMR, MS). The molecular structures of 5 , 8 and 9 were elucidated by X‐ray diffraction analyses.     

Synthese,Struktur und Reaktivität von Bis(dialkylamino)diphosphanen

Synthesis, Structure, and Reactivity of Bis(dialkylamino)diphosphines Starting with the aminochlorophosphines ⁱPr₂N? PCl₂ 1 and (ⁱPr₂N)₂P? Cl 2 , the synthesis of some new functionalized aminophosphines (ⁱPr₂N)₂P? SiMe₃ 3a , (ⁱPr₂N)₂P? SnMe₃ 3b , (ⁱPr₂N)(DMP)P? Cl 4 , ⁱPr₂N? P(SiMe₃)₂ 5 and ⁱPr₂N? P(SiMe₃)Cl 6 is reported. Reactions of 2 with different phosphides yield the aminodiphosphines (ⁱPr₂N)₂P? P(SiMe₃)₂ 7a , (ⁱPr₂N)₂P? P(SiMe₂^tBu)₂ 7b , (ⁱPr₂N)₂P? PPh₂ 8 and (ⁱPr₂N)₂P? PH₂ 9 . The phosphines 3a/b react with halogenophosphines to the aminohalogenodiphosphines (ⁱPr₂N)₂P? PCl₂ 10 , (ⁱPr₂N)₂P? P^tBuCl 11 and (ⁱPr₂N)₂P? P(NⁱPr₂)Cl 12 . The ambivalente aminophosphine 6 gives the aminotrichlorodiphosphine Cl(ⁱPr₂N)P? PCl₂ 13 after condensation with PCl₃, while the reactions with the corresponding lithiumphosphides yield the aminosilyldiphosphines (ⁱPr₂N)(SiMe₃)P? P(SiMe₃)₂ 14a and (ⁱPr₂N)(SiMe₃)P? P(SiMe₂^tBu)₂ 14b . The aminochlorophosphines 2/4 are reductively coupled with magnesium leading to the symmetrically substituted tetraaminodiphosphines (ⁱPr₂N)₂P? P(ⁱPr₂N)₂ 15a and DMP(ⁱPr₂N)P? P(ⁱPr₂N)DMP 15b . The functionalized aminosilyldiphosphine 7a is treated with methanol to yield the diphosphine (ⁱPr₂N)₂P? PH(SiMe₃) 16 and gives the lithium phosphinophosphide (ⁱPr₂N)₂P? PLi(SiMe₃) 17 after metallation with n-BuLi. The compounds are characterized by their NMR and mass spectra and the ³¹P-NMR values of the diphosphines are discussed according to their substituents. The crystal structures of 7b, 8 and 15b showing significantly differing conformations are presented.     

Zur Struktur und Reaktivität von stannylierten Propylaminen und -sulfiden. Kristall- und Molekülstruktur von Bis(3-dimethylchlorostannylpropyl)sulfid S(CH2CH2CH2SnMe2Cl)2

Structure and Reactivity of Stannylated Propyl Amines and Propyl Sulfides. Crystal and Molecular Structure of Bis(3-chlorodimethylstannylpropyl)sulfide S(CH₂CH₂CH₂SnMe₂Cl)₂ The synthesis and reactivity of stannylated propyl amines and propyl sulfides, respectively, E(CH₂CH₂CH₂SnMe₃)₂ ( 1 , E ? NMe; 2 E ? S) and N(CH₂CH₂CH₂SnMe₃)₃ 3 are reported. 1 and 3 react with dimethyl dichlorostannane under thermal cyclisation to 1,5-dimethyl-5-chloro-1aza-5-stannabicyclo[3.3.0^1,5]octane Me(Cl)Sn(CH₂CH₂CH₂)₂NMe 4 and 5-chloro-1-aza-5-stannatricyclo[3.3.3.0^1,5]-undecane ClSn(CH₂CH₂CH₂)₃N 5 , respectively. The reaction of 2 with dimethyl dichlorostannane leads to the formation of bis(3-chloro-dimethylstannylpropyl)sulfide S(CH₂CH₂CH₂SnMe₂Cl)₂ 6 , whereas the treatment of 2 with tin tetrachloride yields the bis(3-di-chloro-methylstannylpropyl)sulfide S(CH₂CH₂CH₂SnMeCl₂)₂ 7 . The ¹H, ¹³C, and ¹¹⁹Sn NMR data are discussed. 6 crystallizes in the ortho-rhombic space group Pna2₁ with the unit cell parameters a = 2275.0(1), b = 733.6(2), c = 1062.0(4) pm, V = 1.77273 nm³, Z = 4. The structure was refined to a final R value of 0.041. Both tin atoms adopt distorted trigonal bipyramidal configurations as a result of intramolecular interactions with the bridging sulphur. The sulphur and the chlorine atoms occupy the apical positions. The Sn? S distances amount to 309.7(4) and 311.8(4) pm.     

Synthese und Struktur von 1,3‐Diisopropyl‐4,5‐dimethylimidazolium‐2‐sulfonat: Ein Carbenaddukt des Schwefeltrioxids

Synthesis and Structure of 1,3‐Diisopropyl‐4,5‐dimethylimidazolium‐2‐sulfonate: A Carbene Adduct of Sulfur Trioxide [1] The stable betaine 1,3‐diisopropyl‐4,5‐dimethylimidazolium‐2‐sulfonate ( 5 ) is obtained through hydrolysis of the 2‐chloro‐1,3‐diisopropyl‐4,5‐dimethylimidazolium chloro‐ sulfite salt ( 4 b ) in the presence of cyanide. The crystal structure analysis of 5 is reported.     

Synthese und Molekülstruktur von Li[(Me2NCH2CH2CH2)4Yb]

Preparation and Structure of Li[(Me₂NCH₂CH₂CH₂)₄Yb] YbCl₃ reacts with dimethylaminopropyl lithium in tetrahydrofuran with formation of Li[(Me₂NCH₂CH₂CH₂)₄Yb]. The X-ray structure determination proves the formation of chelat rings by two of the ligands. The nitrogens of the other two ligands are coordinated to the lithium. The compound crystallizes in the monoclinic space group C2/c with the unit cell parameters a = 27.854(8) Å, b = 9.183(3) Å, c = 20.125(8) Å, β = 96.40° and Z = 8.     

Synthese und Reaktivität von Diphenylphosphanyltrimethylsilylamin Ph2PN(H)SiMe3

Synthesis and Reactivity of the Diphenylphosphanyltrimethylsilylamine Ph₂PN(H)SiMe₃ The trimethylsilyliminotriphenylphosphoran Ph₃P=NSiMe₃ ( 1 ) reacts with sodium in THF under cleavage of one P–C_phenyl bond leading to the P^III‐species [(THF)₃Na(Ph₂PNSiMe₃)] ( 2 ). Reaction with NH₄Br or hydrolysis with water gives the diphenylphosphanyltrimethylsilylamine Ph₂PN(H)SiMe₃ ( 3 ) and in low yields the oxidized byproduct [(THF)Na(OOPPh₂)]_n ( 4 ) that can be synthesised directly in high yields in the reaction of Ph₂POOH and NaH in THF. 3 was reacted with an equimolar amount of Zn{N(SiMe₃)₂}₂ to give [(Me₃Si)₂NZnPh₂PNSiMe₃]₂ ( 5 ). 3 reacts with caesium under phosphorus‐phosphorus bond formation in a reductive substituent coupling reaction to give [(THF)Cs₂{Ph(NSiMe₃)P}₂]_n ( 6 ) where phosphorus(III) is reduced to phosphorus(II). Phosphorus‐phosphorus bond formation to give (Ph₂PNSiMe₃)₂ ( 7 ) where the phosphorus(III) centres are oxidized to P^IV is observed in the reaction of 3 with n‐BuLi and bismuthtrichloride.