Multiplicity germylenes

Because of the known capability of digermenes to insert into multiple bonds3,4, it is reasonable to start the present discussion with the reactions which occur in the photolysis of 26 in the presence of unsaturated trapping agents. Similarly to germylene 16, digermene 28 could insert into the triple bond of thiacycloheptyne 21 with the formation of digermacyclobutene 30. 

Germylenes have long been known to react with multiple bonds such as C=C, C C, and C=0. In addition, insertion reactions into carbon halogen, O H, and N H bonds, are well precedented. In the last 10 years, substantial progress has been made in the reaction with C H bonds. 

Addition of Germylenes to Multiple Bonds. Addition reactions of germylenes to the C=0 of para quinones typically yield alternating 2 1 polymers. An exception was noted for Ge[N(SiMe3)2)2 which gave a 1 1 polymer upon reaction with 1,4-quinones. Cyclic a, /3-unsaturated ketones and ethylene and propylene sulfide have also been found to be excellent monomers for the formation of alternating copolymers. Recall that related reactions with quinones and phenones noted in the Ge-C bond formation Section (3.1.7) lead to the dearomatization of the ring and the isolation of molecular products. For 1,4-napthoquinone, both molecular and polymeric products have been observed (equation 8). 

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