Investigation of IMDA Bicyclizations with Acylcyclopentenes 104 and 111. TBSOTf = tert-butyldimethylsilyl trifluoromethanesulfonate, PPTS = pyridinium p-toluenesulfonate, HBPin = pinacolborane (4,4,5,5-tetramethyl-1,3,2-dioxaborolane), cod = 1,5-cyclooctadiene, PCy3 = tricyclohexylphosphine, DMAP = 4-(dimethylamino)pyridine, DMDO = dimethyldioxirane, TBAF = tetrabutylammonium fluoride.