Spirobiindane skeleton

Rhodium-catalyzed arylative ring-opening/spiroannulation of (3-arylcyclo-butylidene)acetate 23 with NaBPh, involved one C-C bond cleavage, two C-H bond cleavages, and three C-C bond formations to afford ketone 24 possessing a l,l -spirobiindane skeleton (Scheme 3.8) [20]. 

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