Rhodium-Catalyzed Silylative and Germylative Cyclization with Dehydrogenation Leading to 9-Sila- and 9-Germafluorenes: A Combined Experimental and Computational Mechanistic Study
rate constant of dehydrogenative germylation was greater than that of dehydrogenative silylation. Competitive reactions in the presence of 3,3‐dimethyl‐1‐butene indicated that the ratio of dehydrogenative metalation and hydrometalation was affected by reaction temperature when a hydrosilane or hydrogermane precursor was used. Further mechanistic insights of oxidant‐free dehydrogenative silylation, including
The rhodium-catalyzed synthesis of silafluorenes from biphenylhydrosilanes is described. This highly efficient reaction proceeds via both Si-H and C-H bond activation, producing only H-2 as a side product. Using this method, a ladder-type bis-silicon-bridged p-terphenyl could also be synthesized.
Rhodium-Catalyzed Dehydrogenative Germylation of C–H Bonds: New Entry to Unsymmetrically Functionalized 9-Germafluorenes
Rhodium-catalyzed dehydrogenative germylation leading to unsymmetrically functionalized 9-germafluorenes via GeH and CH bond activation is described. Despite the significant achievements made in dehydrogenative functionalization of CH bonds, only a limited number of examples with the fourth-row atomH bonds have been reported. The current method enabled the synthesis of various 9-germafluorene derivatives, including tetracyclic as well as donoracceptor substituted germoles, which may be useful for electronic device applications.