Pd(0)-Catalyzed Cross-Coupling of 1,1-Diboronates with 2,2′-Dibromobiphenyls: Synthesis of 9H-Fluorenes
摘要:
An efficient and mild synthesis of 9H-fluorene derivatives through a Pd(0)-catalyzed cross-coupling reaction of 1,1-diboronates with 2,2'-dibromobiphenyls has been developed. This reaction features high yields, operational simplicity, and mild reaction conditions, thus providing an excellent alternative to published methods for 9H-fluorene synthesis.
9-Phenethylfluorene, 9-phenylethylidenefluorene, β-9-fluorenylstyrene, and spiro-1-(9-fluorenyl)-2-phenyl-cyclopropane have been synthesised and their structure established. Certain erroneous statements about 2-(9-fluorenyl)-1,1-diphenylethene and 2-fluorenylidene-1,1-diphenylethane have been corrected and the isomerisation of these substances compared with that of 9-phenylethylidenefluorene and β-9-fluorenylstyrene
bonding of diarylmethanes to alkenes through a radical pathway. Diaryl compound products can be obtained under mild conditions with good yields. The reaction employed a practical approach by utilizing only 10% potassium -butoxide to synthesize diaryl compounds through a radicalmechanism. The radical nature of this reaction was confirmed through radical capture experiments and EPR. Furthermore, we substantiated