A concise total synthesis of the natural carbazole clauraila A

A short and efficient total synthesis of naturally occurring carbazole clauraila A (1) is described. The approach is designed on the basis of the key regioselective Diels-Alder reaction of the properly substituted exo-2-oxazolidinone diene 3 with acrolein (4) to give the corresponding adduct 2. The latter is converted to functionalised diarylamine 8, which is cyclised to the desired carbazole 1 through a Pd-promoted or -catalysed double C-H bond activation process in a fairly good overall yield.