Germylenes heterocyclic

Cyclic Si-, Ge-, Sn- and Pb-analogs of carbenes and alkenes 99EJI373. Germylenes and germanium double-bonded species in heterocyclic organoger-manium chemistry 99KGS1155. 

The chemistry of germanium(II) amidinates has been summarized in a review article by Kiihl under the title "N-Heterocyclic germylenes and related... 

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... 

The nitrogen heteroatoms in imidazole and some closely related heterocycles can stabilize a carbene center at the 2-position (97AG(E)2162). Thus, 1,3-disubstituted imidazole-2-ylidenes (163)-(170), l,3-dimesitylimidazoline-2-ylidene (171), 1,3,4-triphenyl-1H-1,2,4-triazole-5-ylidene (172), and their silylene (173) and germylene (174) analogues are stable (in the absence of oxygen and moisture) solids with definite melting points, which can be recrystallized from appropriate hydrocarbon solvents. The exception is carbene (163) which is an unstable liquid however, it is stable in solution. 

Formation of Ge- and Sn-heterocycles in reactions of germylenes and stannylenes 91CRV311. 

Three-membered heterocycles of type 161 or 163 can also be used for germylene formation and for the synthesis of germole derivatives <1999JA8811, 1994JOM(482)131>. 

Title Use of Stannylenes and Germylenes as Polymerization Catalysts for Heterocycles... 

Cycloaddition reactions are common routes to the formation of four- to six-membered ring heterocycles. Germylenes/ germenes, and metal germylene complexes " have been utihzed extensively for these reactions (Figure 7). 

Summary Anellation effects on A -heterocyclic silylenes, analogous carbenes, and germylenes are compared. Based on the trends observed, properties of new target molecules are estimated. 

A-heterocyclic germylenes and related compounds 04CCR(248)411. Supramolecular compounds of cucurbituril and chalcogenide cluster aquocom-plexes of molybdenum and tungsten 03IZV987. 

Summary Monoaminosilylenes and bis(diethylamino)silylene are formed by thermolysis of amino-substituted disilanes and characterized by trapping with dienes. In the case of MeSiNMe2, cycloaddition reactions were extended to 1,4-diheterodienes, unsaturated ketones and imines allowing an easy synthetic access to functionally substituted unsaturated silicon heterocycles. The syntheses of an isolable, unsymmetric diaminosilylene and of related germylenes and stannylenes are described. The results are presented and discussed in relation to theoretical work on stabilization of donor-substituted silylenes and recent work on isolable diaminosilylenes done by or in cooperation with other groups. 

---