Based on the analysis of the structures shown in Figure and our hypothesis illustrated in Scheme 1d, we should choose a suitable alkyne to access these architectures. Therefore, the X group of alkyne could be easily switched to a hydrogen atom. Initially, our investigation started by using readily available methyl 1-oxo-2,3dihydro-1H-indene-2-carboxylate (1a) and unprotected terminal alkyne (2a) as the model substrates to evaluate the reaction feasibility (Table ). However, the annulation products were not obtained as expected while using cyclic β-ketoesters and terminal alkynes. This failure was likely a result of self-addition of activated alkynes under basic reaction conditions. Consequently, we hypothesized that the installation of a suitable protecting group that can be easily switched to a hydrogen atom, was extremely important for constructing these architectures. Organosilicon compounds have been well recognized as versatile synthetic reagents that can be functionalized or cleaved under mild conditions. Thus, TMS-substituted alkyne (2b) was chosen to mimic the terminal alkyne 2a. Surprisingly, 3a was generated smoothly with high regioselectivity in 73% yield. The chemical structure of 3a was further confirmed via X-ray crystallography. It is of particular note that the steric hindrance of the protecting group for terminal alkynes had a great impact on the reaction. Thus, when alternative silane-protected alkyne 2c or 2d was used, the corresponding product was not able to be observed, which indicated that the use of TMS-substituted alkyne was critical for this type of ring expansion reaction.