Medium-sized and strained heterocycles from non-catalysed and gold-catalysed conversions of -carbolinesElectronic supplementary information (ESI) available: Spectra for new products. A cif file with details on the X-ray analysis of compound 10a is also included. CCDC XXXXXX. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c2ob25755f

2-Allyl-1-vinyl--carbolines and dihydropyrrolo--carbolines react with activated internal alkynes through novel rearrangement reactions leading to complex polycyclic structures. Favored reaction pathways depend on reaction conditions and on the presence of gold catalysts. In particular, upon reaction with 2 equiv. of the alkyne, new hexacyclic structures 10 are formed with total stereocontrol. Highly strained polycyclic structures are obtained upon reaction of -carbolines with alkynes. Reaction conditions determine the final product.