Germoles, synthesis

The synthesis and reactivities of germoles have been well documented and new aspects of their chemistry have been developed.17-25 Several spirocyclic species have been prepared including the l,l -spirogermole 7, as shown in Equation (14),21 and the compounds 8-10, as shown in Scheme l.20... 

The synthesis of alkali salts of the sterically encumbered germole 98 (Equations (159) and (160)),18 as well as the dilithio salt of tetraphenylgermole 99 (Equation (161)),19 have been reported. The latter species crystallized in two isomorphic forms (99a and 99b, Figure 6) and the dianion was shown to be aromatic. 

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>. 

Owing to the lability of the tin-carbon bond, stannoles were the first heterocyciopentadienes to be transformed into other heteroles boroles , arsoles or stiboles ° and auroles. However, since their synthesis is presently less easy for the C-unsubstituted or alkyl substituted derivatives than in the case of the corresponding siloles or germoles, they are not useful reagents for preparing these heteroles. 

Little has been reported on the formation of organogermanium dendrites and related hyperbranched products. Recently, Tang et al. described the synthesis of hyperbranched materials based on the diacetylene l,l-diethynyl-2,3,4,5-tetraphenyl-germole, 130. The homopolymerization of 130 to homopolymer 131 and and copolymerization with 1-octyne, 132, to copolymer 133 was accomplished (Scheme 39). 

SYNTHESIS OF SILOLES AND GERMOLES VIA DOUBLE TRANS ADDITION... 

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