Continuous Flow Synthesis of Spiro[fluorene-9,9'-Xanthene] Serving as the Organic Light Emitting Diode Emitters and Organic Semiconductors for Kilogram-Scale Production With Flexible and Controllable Selectivity.

Continuous flow chemistry allows for the low-cost and eco-friendly mass production of organic semiconductors. Although spiro[fluorene-9,9'-xanthene] derivatives (SFXs) serve as a role of steric hindrance for the function of stability in OLED technology that has been industrialized and commercialized, it does not investigate their chemical engineering based on the "Huang-Xie method" with continuous flow synthesis technology to achieve scalable production. Herein, we report that kilogram-scale production with exceptional product selectivity (90% for SFX and 100% for BPF) with high throughput rates (648.48 g/h for SFX, 997.62 g/h for BPF). Compared with conventional batch processes, the continuous flow approach for SFX synthesis achieved a 25.48% reduction in raw material costs, solid waste generation by 45.79%, and a 68% shortening of production time. This technology exhibited remarkable environmental advantages, yielding an E-factor of 1.54 kg/kg and a process mass intensity (PMI) of 2.54 kg/kg, representing 94.7% and 91.5% reductions relative to batch processes. Using an upgraded continuous flow platform, we also synthesized high-performance optoelectronic materials SFX-TRZ (84% yield) and BPFG (92.5% yield) from SFX and BPF precursors. This work opens continuous flow synthesis for organic semiconductors with advanced green chemistry principles.