The intended products contain substructures that are embedded in a number of biologically-relevant skeleta. Vicinal 1,2-diamines are common motifs in many drugs and functional molecules, and the 1,2-diaminocyclohexane structure is found in small molecule bioactives such as the anti-coagulant edoxaban and the CCR2 antagonist BMS-741672 14 (Figure ), while derived ureas show activity as, for example, inhibitors of β-glucocerebrosidase. Additionally, the tricycles contain an embedded 1-azaspiro[4.5]decane, a structure found in myriad bioactive natural products such as the immunosuppressive agent FR-901483. 19 We therefore envisaged that the spirotricyclic products might be useful starting points for the synthesis of potentially bioactive compounds, and report herein their successful synthesis through the single-step oxidative dearomatisation. Our investigation started by subjecting the (4hydroxyphenylpropyl) urea 1a to proposed dearomatisation conditions, using phenyliodine(III) bis(acetate)/ bis(trifluoroacetate) (PIDA/PIFA respectively) as oxidants (Table ) in hexafluoroisopropanol (HFIP). While no reaction occurred with PIDA under the conditions shown, we were pleased to see that using PIFA direct conversion to the desired tricyclic structure 2a was observed by NMR analysis (entry 2). The reaction was also successful in other fluorinated solvents (entries 3, 4) and while lower conversions were observed in non-fluorinated solvents (entries 5, 6) the use of a mixed HFIP/dichloromethane solvent system at higher (0.2M) concentration gave acceptable yields. The reaction was carried out on a 7 mmol preparative scale to yield 2a in 68% isolated yield (>1 g). The substrate scope of the reaction was then probed, and the results are shown Table . We first examined the effect of different urea substituents using ureas 1b-j, typically prepared from the reaction between 3-(4-hydroxyphenyl)propylamine and the relevant isocyanate (see Supporting Information). Under the optimised reaction conditions, a range of N-alkyl ureas gave the tricyclic derivatives 2b-2e in moderate to good yield. The presence of an electron-withdrawing N-sulfonyl group resulted in a slightly lower yield (2f, 23%), but pleasingly the primary urea 1g cyclised to give the free N-H tricyclic urea 2g in 64% yield. Finally, a range of N-aryl urea substituents were also tolerated in the reaction, yielding tricycles 2h-j. The structures of 2f and 2g were confirmed by X-ray crystallography (Supporting Information).