Table 1.

Investigation of oxidants and hydride acceptors^a.

Entry	Oxidant	Result	Entry	Oxidant	Result
1	None	9%	5	Isoprene	0
2b	Air	Trace	6	Ag2O	Trace
3c	O2	0	7	CuO	15%
4	NCS	0	8	DCB	21%

^aReaction conditions: 1a (0.25 mmol), 2a (0.2 mmol), Ru(PPh₃)₃Cl₂ (3 mol %), dcypf (3 mol %), K₃PO₄ (1.1 equiv), oxidant (2.0 equiv), solvent (0.2 mL) at 70 °C under N₂ atmosphere. See Supplementary Information (SI) for details. ¹H NMR yield was determined using mesitylene as an internal standard. A ‘trace’ amount of product was noted when the desired product was not clearly detected.

^bThe reaction was performed under air.

^cOxygen balloon was used to provide O₂ gas during the reaction.