... figure Scheme 1. Chemical Structures of 1a and 1aH. ... Coloration was carried out with a UV light (λ = 254 nm, intensity: 4.3 mW/cm –2 ). All chemicals for synthesis were purchased ... in anhydrous THF (15 mL) were added Pd(PPh 3 ) 4 (40 mg, 3 mol %) and a solution of K 2 CO 3 ...