Synthesis and isomerization of CAM photoswitches. Reagents and conditions (a) Trivinylboroxin-pyridine complex, Pd(PPh3)4, K2CO3, DME, 85 °C, 18 h, 90% yield; (b) POCl3, DMF, RT, 1 h, 74% yield; (c) tert-Butyl cyanoacetate, piperidine, EtOH, 78 °C, 1 h, 91% yield; (d) Malononitrile, piperidine, EtOH, 78 °C, 1 h, 88% yield; (e) 3-(Boronic acid pinacol ester)-cyclohex-2-enone, PdCl2(dppf), K2CO3, 1,4-dioxane, 101 °C, 2 h, 41% yield.