## 2 Sequences Based upon Alkynylation and Carbopalladative Insertions
Making use of the aforementioned concept, the intermediary enyne indolone **11** has been transformed into solid state red fluorescent push-pull indolones **12** in a consecutive one-pot three-component sequence (Scheme 5, Table 3) [54]. The acetyl group is cleaved upon workup and isolation. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Entry** & _o_**-Iodo Alkynylanilide** & **Aryl Acetylene** & **Amine** & **Indolones 12 (Yield)** \\ \hline
1 & R1 = Ac, R2 = H & R3 = OMe & piperidine \\
2 & R1 = Ac, R2 = ‘Butyl & R3 = ‘Butyl & piperidine \\
3 & R1 = SO2 Me, R2 = OMe & R3 = Cl & piperidine \\
4 & R1 = Ac, R2 = H & R3 = OMe & morpholine \\
5 & R1 = Me, R2 = H & R3 = Cl & morpholine \\
12e (99%) \\ \hline \hline \end{tabular}  
* The acetyl group is cleaved upon workup and isolation.  
\end{table} 
Table 3: Selected push-pull indolones **12**. **Scheme 5. ** Three-component synthesis of push-pull indolones **12**. Mechanistically, the bicatalytic system of palladium and copper catalyzes an insertion-alkynylation-amination path. Related to these results, [PERSON] and coworkers published a facile entry to alkynoyl _ortho_-iodo anilides using the well-established Ugi four-component reaction [55]. Mechanicality, the bicatalytic system of palladium and copper catalyzes an insertion-alkynylation-amination path. Related to these results, [PERSON] and coworkers published a facile entry to alkynoyl _ortho_-iodo anilides using the well-established Ugi four-component reaction [55]. Based on previous results, [PERSON], [PERSON], and [PERSON] found, when secondary _ortho_-iodo alkynoyl anilides (R1 = H) are used, that intermediate **11** (Scheme 5), formed by the palladium-copper co-catalyzed insertion-coupling, undergoes a transition-metal catalyzed cycloisomerization to give a new class of proto- and metallochromic luminescent 2,4-diarylpyrano[2,3-_b_]indoles **13** (Scheme 6, Table 4) [56]. **Scheme 6. ** Sequentially Pd-Cu-catalyzed insertion-coupling-cycloisomerization domino synthesis of 2,4-diarylpyrano[2,3-_b_]indoles **13**. Over the past decades, the Sonogashira alkynylation has turned out to be the most versatile catalytic synthesis of internal alkynes starting from (hetero)aryl or vinyl halides and terminal acetylenes [57, 58, 59, 60, 61, 62]. Most Sonogashira reactions are bimetallically catalyzed by palladium and copper complexes and, therefore, this unique catalyst system has also been shown to be suitable for CuAAC (Cu-catalyzed alkyne-azide cycloaddition) [63, 64, 65, 66, 67, 68, 69], eventually, in a sequential or consecutive fashion. Sonogashira coupling of various aryl halides with (trimethylsilyl)acetylene followed by fluoride mediated desilylation and subsequent CuAAC represents a fairly general approach to 1,4-disubstituted triazoles **14** in good to excellent yield (Scheme 7) [70]. Besides TBAF, CuF\({}_{2}\) was identified as a fluoride source that could also beneficially catalyze the CuAAC. **Scheme 7. ** Consecutive three-component synthesis of 1,4-disubstituted triazoles **14** via Sonogashira alkynylation-desilylation-CuAAC sequence. The ubiquity of indoles in nature combined with their established pharmaceutical role in drug development has made indole derivatives attractive targets for synthesis. Indoles substituted at _C_-3 [71,72] and their aza analogues [73] are known to exhibit remarkable biological activities. Particularly in the case of azaindoles, their ability to bind to the hinge region of kinases renders them promising structural motifs for kinase inhibition studies [74, 75, 76, 77]. Thus a one-pot multicomponent strategy was developed involving the coupling of _N_-Boc protected 3-iodo NH-heterocycles with (trimethylsilyl)acetylene that furnished the TMS-protected heterocyclic alkynes as intermediates, which, after in situ deprotection, gave rise to terminal alkynes that underwent subsequent CuAAC with an azide to furnish 3-triazoleallyl indoles or aza-indoles **15** (Scheme 8) [78].