**1. Introduction**

Organocatalysis plays a pivotal role in the field of synthetic organic chemistry as well as the pharmaceutical industry through diversifying activation strategies owing to meeting the principles of green chemistry [1–4] in terms of cost-effectiveness, longevity, and less toxic compared to conventional transition metal catalysis [5–8]. In this regard, N-heterocyclic carbene (NHC) plays a major role in diversified organic transformations [9–11].

## **1.1 Renewable chemicals**

Renewable chemicals or "bio-based chemicals" are chemicals obtained from renewable sources, such as agricultural feedstock, agricultural waste, organic waste products, biomass, and microorganisms [12]. In general, in chemical industries, processes include the utilization of fossil resources. As the need for energy consumption and population increasing, limited availability of fossil resources has become a risky task in the low or underdeveloped nations to perform trade. Henceforth, alternative renewable resources such as lignin, hemicellulose, cellulose, starch, and protein have become more focus of utility.
