A convenient one-pot synthesis of C(sp2)–C(sp3)-linked 3D-Grid via an ‘A2 + B3’ approach

The synthesis of fluorene-based 3D-Grid-FTPA has been developed by the one-pot formation of six C(sp2)-C(sp3) bonds through BF3•Et2O-mediated Friedel-Crafts reaction of A2-type DFOH and two B3-type triphenylamines with a total yield of 55%. At the same time, Un-Grid-FTPA (2.7%) and 2D-Grid-FTPA (5.6%) as by-products were also obtained from this synthetic method. In addition, the effect of stereoisomers of DFOH was evaluated to demonstrate that Rac-DFOH is a better A2-type building block to prepare 3D-Grid-FTPA with a relative high yield. Furthermore, 3D-Grid-FTPA shown excellent chemical, thermal, and photo stabilities.