We followingly performed this conversion in bulk phase for comparison purpose. The reactant 1a stirred in a bulk solution was unreacted within 10 min. After one hour reaction in bulk, a different product, benzofused 7membered N-heterocycle 3a from rearrangement of a ring-open intermediate was surprisingly formed in addition to a trace amount of 2a (Figure ). When the bulk reaction was continued overnight, the benzofused N-heterocycle 3a was dominant as well as a minor imine 4a (Figure ). Moreover, the benzofused N-heterocycle 3a was in high stereoselectivity (Figure ). Chemical structures of the benzofused N-heterocycle 3a and imine 4a were characterized by proton and carbon nuclear magnetic resonance spectroscopy (Figure -S40), high-resolution mass spectrometry (Figure -S44) and X-radiation diffractometer (Figure & Figure ). The monitoring of the bulk reaction demonstrated that the yields of the benzofused N-heterocycle product 3a and imine 4a were gradually improved (Figure ). We further investigated this conversion in bulk phase under different conditions. The results (Figure d&f) demonstrated high reaction temperature and large sulfuric acid equivalent were favorable to the rearrangement pathway, and best conversions near to 80% was obtained within 4 hours when the bulk reaction was assisted by 18.4 equiv. sulfuric acid at 60 °C.