Optimization of reaction conditions.

Entry	Variation from the standard conditions	Yield of 2aa/%
1	—	68 (58)b
2	B2pin2 instead of HBpin	14
3	Without depe	Trace
4	dppec instead of depe	44
5	10 mol% PEt3 instead of depe	3
6	25 °C instead of 80 °C	19
7	1 atm CO	64
8	Without [RhCl(cod)]2	Trace
9	Without hν	No reaction
10	395 nm instead of 365 nm	No reaction

^aDetermined by ¹H NMR using 1,1,2,2-tetrachloroethane as an internal standard.

^bIsolated yield.

^cdppe = 1,2-bis(diphenylphosphino)ethane.