Table 1.

Effect of aryl enone structure in photocatalytic crossed cycloadditions with methyl vinyl ketone 2^a

entry	enone	cycloadduct	yieldb	d.r.b
1	R1 = Ph		84%	>10:1
2	R1 = 4-ClPh		82%	>10:1
3	R1 = 4-MeOPh		53%	>10:1
4	R1 = 2-furyl		74%	>10:1
5	R1 = Et		0%	--
6	R2 = Et		70%	6:1
7c	R2 = i-Pr		64%	>10:1
8d	R2 = t-Bu		8%	>10:1
9	R2 = CH2OBn		61%	>10:1

^aUnless otherwise noted, reactions conducted using 2.5 equiv 2 and 5 mol% Ru(bipy)₃Cl₂ in the presence of LiBF₄ and i-Pr₂NEt in MeCN. Irradiation time using a 23 W compact fluorescent bulb at 30 cm was 4 h.

^bIsolated yields and diastereomer ratios are the averaged results of two reproducible experiments.

^c12 h irradiation.

^d24 h irradiation.