Germanium heterocycles

Other five-membered germanium heterocycles were prepared by the Lewis acid-catalyzed C-H insertion of a germylene (Equation (15)),26 thermal dissociation of a germaketenethioacetal and trapping of the resulting germy-lene 11 (Equation (16)),27 and from the zircona-bicyclic complexes 12 and 13 (Scheme 2 and Equation (17)).28... 

In Section 4.24.2 the literature from 1982 to the beginning of 1994 (according to Chemical Abstracts) is considered. Earlier data concerning five-membered rings with three or more heteroatoms including at least one Ge, Sn or Pb atom are scarce and there is no information in CHEC-I on these heterocycles. Valuable data on germanium heterocycles can be found in the monograph by Lesbre et al. 424-01 > and some of these data have been included in this section. Tin and... 

Germanium heterocycles possessing multiply bonded Ge-atoms 90-CRV283. 

Silicon and germanium heterocycles, antitumor activity of 87-KFZ402. 

Dimer formation was also reported for the photolysis of the germanium heterocycle [Eq. (31)] (23) but not for tellurophene. Lack of reactivity in this latter compound was ascribed to aromaticity of the heterocycle. Tellurophene also undergoes electrophilic substitution at the a position in formylation, acetylation, and trifluoroacetylation reactions (121). 

A selenoetherification approach similar to the mercury-catalyzed cyclizations utilized for the preparation of aza silicon and germanium heterocycles has been reported. Thus, dichloromethyl-(chloromethyl)silane was treated with phenylmagnesium bromide followed by allylmagnesium bro-... 

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