PdCl 2 (dppf) (5 mol%) NaOAc (2.5 equiv) DMSO, 80 ºC The aryl-substituted BMIDA alkyne components can also be accessed via metalation/borylation or via a simpler Sonogashira coupling of the commercially available acetylene BMIDA (see SI). Regioselectivity was unequivocally established by X-ray crystallography (3 and 4, Scheme 2) and NMR, showing that the BMIDA occupies the 2-position consistent with a larger steric footprint of this unit in comparison to the alkyl/aryl groups. A demonstration of the utility of the 2-BMIDA indole products is shown in Scheme 3. The sulfa drugs are a particularly important class of antibiotics. The developed methodology enables the rapid, regioselective synthesis of the sulfa drug chemotype, included marketed compound 37 via annulation and subsequent Suzuki-Miyaura cross-coupling (Scheme 3a). Importantly, while a Larock approach to 38 could be envisaged via direct heteroannulation using the appropriate diaryl alkyne, steric issues lead to low yields for diaryl alkynes and, in addition, the subtle electronic differences lead to regioisomeric mixtures in these diaryl systems. Finally, this annulation/cross-coupling approach can be deployed to enable the modular synthesis of the Aspidosperma alkalois goniomitine (Scheme 3b). Annulation using alkyne 38 delivers indole 39 on multigram scale. Cross-coupling with lactam fragment 40 provided 41, establishing the full carbon framework needed for the natural product. Hydrogenation, cyclization, and deprotection rapidly provided goniomitine (42). Importantly, intermediate 41 can be potentially diverted to other members of the Aspidosperma family following established approaches. 27 Scheme 3. Utility of the process in drug and natural product synthesis.