1-Allylgermatrane. Synthesis, Structure and Reaction with Diazomethane

Abstract

Reaction of allyltribromogermane (2), readily available from dibromo(1,4-dioxane)germanium(II) (1) and allylbromide, with tris(2-tributylstannoxyethyl)-amine (4) gives 1-allylgermatrane (3) in almost quantitative yield. 3 crystallizes from n-pentane as a colourless crystalline solid which was characterized by 1H and 13C NMR spectroscopy and by an X-ray crystal structure study. The “atrane” skeleton shows a strong conformational disorder; the Ge-N distance of 2.208(3) Å suggests the presence of a coordinative Ge-N bond. Treatment of 1-allylgermatrane (3) with CH2N2 in the presence of catalytic amounts of Pd(OAc)2 affords 1-cyclopropylmethylgermatrane (5) in high yield

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

“…This behaviour is analogous to that observed for 1-allylgermatrane [2] and 1-fluorenylgermatrane [1] and is assumed to be a reflection of the relative bond strength of the Ge±O ring bonds. In the case of 13 a peak of highest intensity corresponds to the parent ion resulting from the loss of one methyl group.…”

9-Silyl(-Germyl,-Stannyl) Substituted Derivatives of 1-(9-Fluorenyl)- germatranes. Synthesis, Characterisation, and Crystal Structures

“…The molecular structures of the two (isostructural) compounds are shown in Fig. 1 and 1.964(6) A 14 are somewhat smaller, but in the case of the silylated derivative this distance is almost identical to that observed for a closely related ger matrane N[CH2CH20 ]3G eC i3H9 (1.991(3) A) [ 13], Typical conformational disorder of the germa trane cage has been observed for both 2 and 14 [ 11,12]. All five-membered rings of the atrane skeleton possess "envelope"-like conformation.…”

“…1H NM R (CDCI3): 6 (10,11) were synthesized by the re action o f the corresponding fluorenes (12,13) with NBS.…”

New synthetic routes to allylic germatranes

“…The likely products of these reactions are of interest to us because allylic germanium trichlorides are precursors to allylic germatranes, reagents with potential application in cross-coupling reactions. Although allylic germanium trihalides are available from the reaction of GeX 2 AE dioxane with allylic halides [8] we have examined the reactions of a number of allylic trialkylstannanes with germanium(IV) chloride in the hope that these reactions would prove more convenient.…”