Step 2: tert-butyl thiazole-2-carbamate (1.0 g, 5.0 mmol) was dissolved in tetrahydrofuran (THF) and cooled to -78 °C. To this solution, freshly prepared lithium diisopropylammonium (LDA, 2.1 eq.) was slowly added and the reaction mixture was stirred at this temperature for 1 hour. Subsequently, tributyltin chloride (1.62 g, 5.0 mmol) was added dropwise and stirring was continued at -78 °C for 24 hours. Upon completion of the reaction, the reaction was quenched by the addition of 100 mL of saturated aqueous ammonium chloride (NH4Cl) and extracted with ethyl acetate (EtOAc, 3 x 100 mL). The organic layers were combined, washed with saturated brine, dried over anhydrous sodium sulfate (Na2SO4), and concentrated under reduced pressure to afford tert-butyl (5-(tributylstannyl)thiazol-2-yl)carbamate as a brown solid (2.25 g, 92% yield). Electrospray ionization mass spectrometry (ESIMS): m/z 491 ([M+H]+).
