Table 1.

CEES oxidation with bio-inspired Mo and W dithiolene catalysts.^a

Entry	Catalyst	Time	Conversion (%)b	Sulfoxide selectivity (%)c
1	[MoO2(mnt)2]2- (1)	5 min	100	100
2	[MoO2(mnt)2]2- (1)	1 h	100	94
3	None	1 h	3	100
4d	[WO2(mnt)2]2- (2)	1 h	0	n/a
5	[WO2(mnt)2]2- (2)	1 h	100	100
6	[MoO2(bdt)2]2- (3)	1 h	100	100
7	[WO2(mnt)2]2- (2)	15 min	100	100
8	[MoO2(bdt)2]2- (3)	5 min	100	100

^aReaction conditions: CEES (2.0 mmol), H₂O₂ (2.1 mmol), Catalyst (1.5 mol%), MeOH (6 mL), room temperature.

^bDetermined by GC using mesitylene as an internal standard.

^cDetermined by GC. Sulfoxide selectivity = [%sulfoxide / (%sulfoxide + %sulfone)]*100.

^dO₂(g) in place of H₂O₂.