Table 1.
Uniform conditions unless otherwise noted: 2 eq diazo compound, 2 mol% Rh2(OAc)4, 30 min diazo compound addition at 60 °C, then reflux for 4 h, then rt DDQ addition
0.5 mol% Rh2(OAc)4 used
4 eq of diazo compound used
diazo compound added at reflux
3 eq of diazo compound used
refluxed overnight after diazo compound addition