G. S. Zaitseva

Titanium complexes based on chiral enantiopure dialkanolamines: synthesis, structures and catalytic activity

New chiral enantiopure tridentate ligands (dialkanolamines) RN(CHR3CR1R2OH)(CHR4CR5R6OH) 10–17 were synthesized by the opening of the epoxide ring by the action of the amines or alkanolamines. Titanium complexes, viz. [RN(CHR3CR1R2O)(CHR4CR5R6O)]Ti(O-i-Pr)218–23 and [RN(CHR3CR1R2O)(CHR4CR5R6O)]2Ti 25–31 were synthesized by treatment of Ti(O-i-Pr)4 with one or two equivalents of corresponding dialkanolamines. Complex (R)-PhCH(Me)N(CH2C(Me)2O)2TiCl2*HNMe224 was obtained from the reaction of one equivalent of dialkanolamine 10 with (Me2N)2TiCl2. The composition and structure of all novel compounds were established by 1H and 13C NMR spectroscopy as well as elemental analysis. The possible solution structures of 18–31 are discussed. The single-crystal X-ray diffraction study of 23, 25–28, 30, 31 indicates monomeric structures in the solid state. Chiral complexes 20, 22, 23, 25, 26, 30 were tested as chiral catalysts in the Abramov reaction and demonstrated moderate enantiomeric activity.

New approach to 1-(phenylethynyl)germatranes and 1-(phenylethynyl)-3,7,10-trimethylgermatrane. Reactions of 1-(phenylethynyl)germatrane with N-bromosuccinimide and bromine

Abstract Reaction of N(CH 2 CHRO) 3 GeBr ( 2a, b ) with LiCCPh affords N(CH 2 CHRO) 3 GeCCPh ( 1a , b ) ( a , R=H; b , R=Me). Compound ( 1b ) was also obtained by treatment of Cl 3 GeCCPh ( 3 ) with N(CH 2 CHMeOSnEt 3 ) 3 ( 4 ). ( 1a ) reacts with N -bromosuccinimide to yield N(CH 2 CH 2 O) 3 GeC(Br) 2 C(O)Ph ( 5 ). Cis -N(CH 2 CH 2 O) 3 GeC(Br)C(Br)Ph ( 6 ) is formed by the reaction of 1a with Br 2 in equivalent amounts. All compounds were characterized by 1 H- and 13 C-NMR spectroscopy and mass spectrometry. Single crystal structures of 1a and 6 were determined by X-ray diffraction studies.

Preparation of germatranyl triflates: reactions of germatranes N(CH2CHRO)3X (X=Br, OTf, OSiMe3; R=H, Me) with lithium reagents

Abstract New germatranes N(CH 2 CHRO) 3 GeOTf ( 4a , R=H; 4b , R=Me) were prepared in quantitative yield by treatment of N(CH 2 CHRO) 3 GeOSiMe 3 ( 2a and 2b ), with Me 3 SiOTf. The reactions of germatranes N(CH 2 CHRO) 3 GeX [ 3a , X=Br, R=H; 4a , X=OSO 2 CF 3 , R=H; 4b , X=OSO 2 CF 3 , R=Me; 2a , X=OSiMe 3 , R=H; 2b , X=OSiMe 3 , R=Me] with LiY reagents were studied. A series of germatranes N(CH 2 CHRO) 3 GeY [ 5a , R=H, Y=Ind (indenyl); 5b , R=Me, Y=Ind; 6a , R=H, Y=N(SiMe 3 ) 2 ; 6b , R=Me, Y=N(SiMe 3 ) 2 ; 7a , R=H, Y=Cp (cyclopentadienyl); 7b , R=Me, Y=Cp; 8a , R=H, Y=Flu (fluorenyl); 9a , R=H, Y= t -Bu] were obtained by nucleophilic substitution with the corresponding LiY reagent. Reactions of N(CH 2 CHMeO) 3 GeOSiMe 3 ( 2b ) and N(CH 2 CH 2 O) 3 GeBr ( 3a ) with excess n -BuLi and of N(CH 2 CH 2 O) 3 GeOSiMe 3 ( 2a ) with excess LiNMe 2 led to the formation of n -Bu 4 Ge and (Me 2 N) 4 Ge. The structures of new germatranes 4a , 4b , 6b and 7b were confirmed by NMR spectroscopy, mass spectrometry and elemental analyses.

A facile synthesis of 1-halo- and 1-organoxygermatranes

Abstract Interaction of the readily available 1-trimethylsilogermatranes ( 1a, 1b ) with various halogenating reagents (Me 3 SiBr, Me 3 SiI, HF and SOCl 2 ) has given the 1-halogermatranes ( 2a–2f ). The 1-halogermatranes ( 2a–2b ) have been converted into the corresponding 1-organoxygermatranes by treatment with trialkylalkoxystannanes ( 3a–3f ). The corresponding 1-organoxygermatranes ( 4d, 4e, 4f ) were made by interaction of 1-hydroxygermatrane monohydrate with the corresponding hydroxy derivatives).

Synthesis and characterization of 3- and 4-phenylgermatranes: X-ray crystal structures of N(CH2CH2O)2(CH2CHPhO)GeZ (Z=F, OSiMe3, CCPh) and N(CH2CH2O)2(CHPhCH2O)GeOH

Abstract Reaction of excess of product A [(HOCH2CH2)2NCH2CH(Ph)OH (1):(HOCH2CH2)2NCH(Ph)CH2OH (2)=9:1] with GeCl4 led to a mixture of 1-chloro-3-phenylgermatrane (3) and 1-chloro-4-phenylgermatrane (4). Compound 4 was isolated in yield 9% from this mixture. Reaction of (EtO)3GeCl with product A gave 3 in yield 55%. 1-(Phenylethynyl)-3-phenylgermatrane (5) was prepared in yield 31% by treatment of (EtO)3GeCCPh with product A. Reaction of product A with mixture of GeO2 and H2O produced N(CH2CH2O)2(CH2CHPhO)GeOH (6) in yield 73%. The presence of N(CH2CH2O)2(CHPhCH2O)GeOH (7) among the products of this reaction was confirmed by 1H-, 13C-NMR spectroscopy and X-ray analysis. N(CH2CH2O)2(CH2CHPhO)GeF (8) is formed by the treatment of 6 with BF3·Et2O. N(CH2CH2O)2(CH2CHPhO)GeOSiMe3 (9) was obtained by silylation of 6 with (Me3Si)2NH or Me3SiCl–Et3N. Refluxing of a suspension of 6 in xylene with continuous removal of water by azeotropic distillation afforded [N(CH2CH2O)2(CH2CHPhO)Ge]2O (10). 9 reacted with SOCl2, Me3SiBr and Me3SiOTf to give N(CH2CH2O)2(CH2CHPhO)GeX (3, X=Cl; 11, X=Br; 12, X=OTf), respectively. Reaction of 11 with Et3SnOMe led to the formation of N(CH2CH2O)2(CH2CHPhO)GeOMe (13). Germatranes N(CH2CH2O)2(CH2CHPhO)GeY [14, Y=Flu (fluorenyl); 15, Y=N(SiMe3)2] were obtained from the nucleophilic substitution of the substituent X in N(CH2CH2O)2(CH2CHPhO)GeX (X=OSiMe3, Br) with the corresponding LiY. All compounds were characterized by 1H- and 13C-NMR spectroscopy and mass spectrometry. Single-crystal structures of 5 and 7–9 were determined by X-ray diffraction studies.

Silylated and germylated cyclopropanones

Abstract The synthesis of trimethylsilyl- and germyl-cyclopropanones, by treating diazomethane with the corresponding trimethyl ketene, and their ring expansion to cyclobutanones are described.

Reaction of digermanes and related Ge-Si compounds with trifluoromethanesulfonic acid: synthesis of helpful building blocks for the preparation of Ge-Ge(Si)-catenated compounds

Abstract The reaction of a series of compounds, Ar3 Ge-MR3, 1–4 (Ar=Ph, p-Tol, M=Si, Ge, R=Ph, Me, tBu), with one equivalent of trifluoromethanesulfonic acid (HOTf) was investigated. The corresponding triflates were isolated in several cases. The molecular structure of Ph3 Ge-GePh2 OTf (5) in solid state was investigated by X-ray analysis. The triflates were converted to the corresponding chlorides under the action of ammonium chloride.

Reaction of silyl- and germyl-ketenes with silyldiazomethanes

Abstract The reaction of trialkylsilyl- and trialkylgermyl-ketenes with trialkylsilyldiazomethanes proceeds stereoselectively to give one of two feasible stereoisomers, the Z -2,3-bis(Si,Ge)-substituted cyclopropanone. The addition of nucleophilic reagents such as benzyl alcohol, LiAlH 4 or (trimethylsilyl)dialkylphosphites is highly stereoselective and is a convenient method for assigning the stereochemical configuration of 2,3-substituted cyclopropanones.

Synthesis and Characterization of Group 14 1-Haloazametallatranes

The reaction between MHal4 (M = Ge, Sn; Hal = Cl, Br) and N(CH2CH2NRLi)3 (R = Me, SiMe3) yields 1-haloazametallatranes 1−8, N(CH2CH2NR)3M−Hal (1, M = Ge, Hal = Cl, R = Me; 2, M = Ge, Hal = Br, R = Me; 3, M = Ge, Hal = Cl, R = SiMe3; 4, M = Ge, Hal = Br, R = SiMe3; 5, M = Sn, Hal = Cl, R = Me; 6, M = Sn, Hal = Br, R = Me; 7, M = Sn, Hal = Cl, R = SiMe3; 8, M = Sn, Hal = Br, R = SiMe3). The composition and structures of the new compounds were established by elemental analyses, 1H and 13C NMR spectroscopy and mass spectrometry. Single crystal structures of 1 and 3 were determined by X-ray diffraction studies: both compounds show transannular Ge−Nax interactions. (© Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)

Synthesis of 1-cyclopropylmethylsilatrane and 1-cyclopropylmethyl-3,7,10-trimethylsilatrane. Crystal structure of 1-cyclopropylmethylsilatrane

Abstract 1-Cyclopropylmethylsilatrane ( 2a ) and 1-cyclopropylmethyl-3,7,10-trimethylsilatrane ( 2b ) have been prepared in good yields by the reaction of the corresponding 1-allylsilatranes N(CH 2 CHRO) 3 SiCH 2 CHCH 2 ( 1 ) (R  H ( a ), Me ( b )) with diazomethane in the presence of Pd(OAc) 2 as a catalyst. 1-Cyclopropylmethylsilatrane ( 2a ) has also been synthesized from the reaction of cyclopropylmethyltriethoxysilane ( 3 ) with triethanolamine. Compounds 2a, 2b and 3 have been characterized by 1 H and 13 C NMR spectroscopy and elemental analyses. An X-ray structure determination of 2a indicates the presence of an N → Si bond length of 2.149(4) A.