A gold-triggered dearomative spirocarbocyclization/Diels-Alder reaction cascade towards diverse bridged N-heterocycles

A rapid approach for the diversity-oriented synthesis of complex bridged polycyclic N-heterocycles from readily available starting materials in two operational steps has been developed. This strategy firstly introduces molecular diversity by an Ugi four-component reaction, and then achieves these bridged N-heterocycles via an efficient gold-triggered chemo- and diastereoselective cascade non-oxidative ortho -dearomative spirocarbocyclization/Diels-Alder reaction sequence. The application of microwave irradiation for this cascade process efficiently shortens the reaction time to 10 minutes and improves the diastereoselectivity. An efficient chemo- and diastereoselective gold-triggered post-Ugi non-oxidative ortho -dearomative spirocarbocyclization/Diels-Alder reaction cascade sequence has been developed to deliver diverse bridged polycyclic N-heterocycles.