Table 2. Screening of Solvents for Amide Couplings with DPDTC and Solubilities of 1a^a.

entry	solvent	NMR yield 1 (%)	solubility of acid in solvent (M)
1	MIBK	100	0.1
2	MEK	46	0.2
3	CPME	95	0.1
4	THF	97	1
5	iPrOAc	76	0.1
6	tBuOH	79	0.5
7	EtOAc	98	0.1
8	2-MeTHF	98	0.75
9	toluene	100	not soluble
10	MTBE	100	0.1

^aNMR yields using 1,3,5-trimethoxybenzene as internal standard.