Synthesis of (Deoxy)difluoromethylated Phosphines by Reaction of R 2 P(O)H with TMSCF 3 and Their Application in Cu(I) Clusters in Sonogashira Coupling.

R 2 PCF 2 H ligands and their R 2 P(O)CF 2 H precursors were synthesized from R 2 P(O)H with TMSCF 3 by simply modulating the H 2 O concentration via deoxydifluoromethylation and difluoromethylation. The air sensitive R 2 PCF 2 H phosphines can be stabilized in Cu(I) clusters as ligands. Within these Cu(I) clusters, the Sonogashira cross-coupling reaction can proceed fast and efficiently using terminal alkynes and aryl iodides within 15 min at room temperature under air to give a variety of diaryl(alkyl)acetylenes in good yields (49 examples, yields of ≤99%). Six of the internal alkynes present in drug precursors can be obtained using this protocol in good yields. The mechanism is proposed on the basis of control experiments.