Cesium carbonate → 5-(3,3-Dimethyl-but-1-ynyl)-3-[2-(ethoxy-methyl-phosphinoyl)-ethylamino]-thiophene-2-carboxylic acid methyl ester

Participants

Reaction Steps

5-(3,3-Dimethyl-but-1-ynyl)-3-iodo-thiophene-2-carboxylic acid methyl ester (669 mg, 1.92 mmol), Pd(OAc)2 (64 mg, 0.288 mmol), BINAP (179 mg, 0.288 mmol), and Cs2CO3 (1.56 g, 4.8 mmol) were combined in a sealed tube. A solution of (2-amino-ethyl)-methyl-phosphinic acid ethyl ester (578 mg, 3.85 mmol) in toluene (14 mL), which had been degassed by bubbling argon through it for 30 minutes, was added. The sealed tube was purged with argon and then sealed. The tube was placed in a 120° C. oil bath. The reaction was stirred overnight, then cooled to room temperature and filtered through filter paper. The residue was stirred vigorously with EtOAc and then the EtOAc was passed through filter paper. The combined filtrates were concentrated and 5-(3,3-Dimethyl-but-1-ynyl)-3-[2-(ethoxy-methyl-phosphinoyl)-ethylamino]-thiophene-2-carboxylic acid methyl ester (466 mg, 66%) was isolated by silica gel column chromatography (MeOH/EtOAc) as a green crystalline solid.

Provenance & Evidence