Synthesis of (Deoxy)difluoromethylated Phosphines by Reaction of R2P(O)H with TMSCF3 and Their Application in Cu(I) Clusters in Sonogashira Coupling

R2PCF2H ligands and their R2P­(O)­CF2H precursors were synthesized from R2P­(O)H with TMSCF3 by simply modulating the H2O concentration via deoxydifluoromethylation and difluoromethylation. The air sensitive R2PCF2H 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.