Lewis and Brønsted basicity of phosphine-diazomethane derivatives†
The compounds EtOC(O)CHNNPR3 (R = Ph 1, Cy 2, tBu 3) were prepared via the reactions of the diazomethane and a phosphine. In subsequent reactions with B(C6F5)3, the compounds 2 and 3 are shown to exhibit Lewis basicity at the carbonyl oxygen affording EtOC(O(B(C6F5)3))CHNNPR3 (R = Cy 5, tBu 6). Reactions of 5 and 6 with water or phenol illustrated the Brønsted basicity at the nitrogen atom adjacent phosphorus, affording the compounds, [EtOC(O)CHNNHPR3][HOB(C6F5)3] (R = Cy 7, tBu 8) and [EtOC(O)CHNNHPR3][PhOB(C6F5)3] (R = Cy 9, tBu 10), respectively. The formulation of these products is confirmed via spectroscopic and crystallographic studies, and insight is garnered from computations.