TABLE 1.

Reaction condition optimization studies. ^a

Entry	Base	Solvent	Yield b (%)
1	Cs2CO3	EA	15
2	Et3N	EA	—
3	NaHCO3	EA	38
4	Na2CO3	EA	66
5	NaOH	EA	11
6	K2CO3	EA	80
7	NH4HCO3	EA	82
8	NH4HCO3	DCM	65
9	NH4HCO3	CHCl3	52
10	NH4HCO3	Et2O	61
11	NH4HCO3	Toluene	73
12	NH4HCO3	DCE	70
13	NH4HCO3	MTBE	85
14	NH4HCO3	CCl4	54
15 c	NH4HCO3	MTBE	88
16 d	NH4HCO3	MTBE	80

^aAll reactions were conducted with 0.4 mmol of 1a (1.0 equiv.), 0.44 mmol of 2a (1.1 equiv.), and 1.2 mmol of base in 4.0 ml of solvent at rt.

^bYield of isolated compound 3a after chromatography.

^cThe reaction was conducted at 40°C.

^dThe reaction was conducted at 50°C.

All the reactions were conducted with 0.4 mmol of 1 (1.0 equiv.), 0.44 mmol of 2 (1.1 equiv.) and 1.2 mmol of base in MTBE (4.0 mL) at 40°C. Yields are those of the isolated products 3a–3n after column chromatography.