Substrate scope of alkynes^a.

^aConditions: 1 mol% Pd₂(dba)₃, 2 mol% ligand L4, and 4 mol% Ph₂P(O)OH in 1 mL toluene were stirred for 10 min in an argon atmosphere. 0.25 mmol alkynes 1b–1t and 1.0 mmol 2a were added, and the mixture was stirred at 60 °C for 20 h. Isolated yields. Determined by HPLC analysis.

^b80 °C was used instead.