Synthesis of Germatranyl Derivatives of Esters of Carboxylic Acids via Organometallic (Si, Ge, Sn) Reagents

Abstract

Trialkylstannyl esters of tris (2-hydroxyalkyl)amines, N(CH2CHROSnAlk,), (9-11) (R = H, Me; Alk = Et, Bu), react with X3GeC(R1)(RZ)COOR3 (12-17) (X = C1 or Br; R1, R' = H, Me, Ph, SiMe3, COOEt; R3 = Me, Et) to give esters of a-germatranylcarboxylic acids, N(CHzCHR0)3GeC(R1)(R2)-COOR3 (1-8), in high yields. The synthesis of esters 12-17 is reported. Esters of a-germatranyldiphenylacetic acid 24 and 25 can be obtained by treatment of diphenylketene with Et,SnOMe to give in situ Et3SnC(Ph,)COOMe (23), followed by reaction with GeC14 to give in situ Cl3GeC(Phz)COOMe (22) and further reactions with 9 or 11, respectively. Reduction of germatrane 6 with LiAlH, in diethyl ether leads to cleavage of the germanium-carbon bond with subsequent formation of (2-hydroxyethy1)trimethylsilane. The crystal structures of 3, 6, and 7 are reported. 1-Acyloxygermatranes 26 and 27 are obtained by treatment of l-methoxygermatrane (28) with diphenyl-and dichloroacetic acid, respectively.Interest continues in metallatranes N(CH2CHAlk)3M -Y (M = Si, Ge), having been reported some years ago for the first time; the main focus has been the nature of the transannular M-N bond [']. However, theoretical aspects of the research on metallatranes did not render synthetic approaches to a second-order problem. Moreover, many silatranes and germatranes show biological activity, which makes them interesting for medicinal chemistry and pharr n a c o I~g y~~-~] .So far, functionalizcd silatranes and germatrane~[~-"I, e.g. metallatranes with a functional group (e.g. C=O, C=C) in the p position to the metal atom, have not been studied in detail. Similar compounds belong to a more general class of a,x-conjugated systems, with characteristic features of the relatively labile metal-carbon bond and (e.g. in the case of p-0x0 derivatives) with the ability to undergo isomeric transformations under catalytic conditions or on heati11g[12-141. Whereas the synthesis and reactivity of 1-aIIylsi1-atranes were subject of numerous investigations, there is almost no information available on the chemistry of l-allylgerniatrane: only cleavage reactions of the Ge-C bond in 1 -allylgermatrane were reported" l]. Our investigations included reactions at the C=C bond of I-allylmetallatranes which occur with retention of the "atrane" skeleton and the metal-carbon bond, e.g. the cyclopropanation of l-allylmetallatranes (M = Si, Ge) [lo~'l].In this paper we rcport on the synthehis and properties of the series of esters of a-germatranylcarboxylic acids 1-8, starting from trihalogenogermanium dcrivatives 12-17, and tris(2-trialky1stannoxyalkyl)amines 9-11. Other organotin reagents, e.g. Et?SnOMe, were also used in the synthesis of I-acyloxygermatranes 26 and 27. In addition, the crystal structures of compounds 3, 6, and 7 are discussed in comparison.We have recently described the synthesis of the first of p0x0 derivatives of metallatranes: silatranylacetaldehyde and 3,7,1O-trimethylsilatranylacetaldehyde, N(CH2CHR0)3Si-CH2CH0 (R = H, Me) [6]. The compounds are air-stable and unde...

Synthesis and Characterisation of 1-[9-(H, Me3Si, Me3Ge, Me3Sn)9-Fluorenyl]-3,7,10-trimethylgermatranes. The Crystal Structure Analysis of 1-(9-Fluorenyl)-3,7,10-trimethylgermatrane

“…In the case of 13 a peak of highest intensity corresponds to the parent ion resulting from the loss of one methyl group. A cluster of peaks at m/z 130 has been attributed to the ion GeN(CH 2 ) 3 + , which is consistent with a germatrane structure. In the case of 1±3 and 1 A, the molecular ion peak carries a relatively small portion of the ion current (2±9%).…”

“…(S,S,S)-(+)-Triisopropanolamine (16) was obtained as described in [10], starting from commercial (Merck) (S)-(±)-propylene oxide and (S)-(+)-amino-2-propanol; m. p. 102°C; NMR (300 MHz, C 6 D 6 ): 13 Tris(2-trialkylstannoxypropyl)amines (7,8) were prepared according to a described procedure starting from triisopropanolamine and Alk 3 SnOMe (Alk = Et, Bu) [3].…”

“…The temperature was allowed to rise to 25°C. Stirring was continued for 24 h, after that solvents and GeCl 4 [15], V = 3991.7(2) A Ê 3 , space group P2 1 /c, Z = 8, D c = 1.418 g/cm 3 , F(000) = 1776, l(Mo±Kα) = 1.557 mm ±1 . Data collection, structure solution and refinement: a total of 19547 reflections (5707 unique, R int = 0.0518) were measured using graphite monochromatized Mo±Kα radiation (k = 0.71073 A Ê ) at 100.0(2) K. Data were collected in the range 1.58 < q < 23.29 (±12 ≤ h ≤ 13, ±20 ≤ k ≤ 15, ±20 ≤ 1 ≤ 20).…”

Bromination of silatranyl‐, germatranyl‐, silyl‐, and germyl‐phenylacetylenes

“…According to our knowledge this is the first case of shortening of 3 Ge X (1.920(8) and 1.98(2) A, respectively [7]). Of interest, the Ge C distance in 2 is the shortest one among the previously found in germatranes containing N Ge C moiety (1.92-2.01 A) [7,51,52].…”

Two germatranes with bulky substituents

“…The in¯uence of the intermolecular contacts can be demonstrated by methyl (germatranyl)trimethylsilylacetate (Zaitseva et al, 1997) and (penta¯uorophenyl)germatrane (Kultyshev et al, 2004) (N1ÐGe1ÐC7 = 175.73 and 176.29 , respectively). In the case of the former compound, the acetate group forms four CÐHÁ Á ÁO contacts (CÁ Á ÁO 9 3.5 A Ê , HÁ Á Á O 9 2.6 A Ê and CÐHÁ Á ÁO = 107±146 ) as well as three HÁ Á ÁH and CÁ Á ÁH contacts (HÁ Á ÁH 9 2.2 A Ê and CÁ Á ÁH 9 3.1 A Ê ).…”