Table 2. Solvent effects for the Zn(OTf)₂-mediated conversion of 1c into 2a and 3c ^a .

Entry	Solvent	Time	Yield b (%)			Recovery (%)	2a : 3c
			2a	3c	4a
1	t-BuOH	24	45	55	5	—	45 : 55
2	2-BuOH	8	25	70	5	—	26 : 74
3	i-PrOH	8	23	68	5	—	25 : 75
4	EtOH	24	31	63	5	—	33 : 67
5	MeOH	24	13	40	3	37	25 : 75
6	CH3CN	8	84	7	7	2	92 : 8
7	THF	24	80	6	7	6	93 : 7

^aAll reactions were performed using 1c (0.2 mmol) and Zn(OTf)₂ (0.2 mmol) in 1 mL of each solvent at 60 °C.

^bDetermined by ¹H-NMR analysis.