**2. Challenges facing pyrimidine synthesis**

Although widely used, the existing protocols for the synthesis of pyrimidines were labor intensive, oftentimes impractical, inefficient or incompatible with a number of functional groups, harsh reaction conditions, involvement of transition metal catalysis, multistep synthesis of the starting material, or need for inert gas protection, remain as shortcomings in known pyrimidine synthesis (**Figure 1**).
