The enantioselective synthesis of silicon-stereogenic benzo-furanylmethylidene-benzoxasiloles was achieved with moderate enantioselectivity by the cationic rhodium(I)/(S)-BINAP complex-catalyzed desymmetrization of symmetrical bis(2-ethynyl-phenol)silanes, possessing the tert-butyl and methyl groups on the silicon atom. This reaction involves 1,2-silicon/1,3-carbon migrations and oxycyclization, and the 1,2-silicon migration constructs the stereogenic silicon center. The thus obtained benzofuranylmethylidene-benzoxasiloles with the electron-donating methoxy, methyl, and phenyl groups on two benzene rings showed good fluorescence quantum yields in solution state, on the other hand, that with the electron-withdrawing trifluoromethyl groups on two benzene rings showed good fluorescence quantum yield in solid state.
- Fluorescent chiral organosilicon
- Rhodium catalysis
- Silicon-stereogenic compounds
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