The present manuscript, entitled “Transition Metal-Free [3+2] Cycloaddition Approach Towards Efficient Synthesis of Trisubstituted Pyrrole Derivatives from β-Chlorovinyl Aldehydes” by Prof. Singh and co-workers, describes an unexplored [3+2] cycloaddition between 3-phenylpropiolonitrile and tosylmethyl isocyanide (ToSMIC). While [3+2] cycloadditions between alkynes and isocyanides are well documented in the literature, the reaction of 3-phenylpropiolonitrile with isocyanides has not been much explored. In this manuscript, the authors present a novel methodology to access a wide range of trisubstituted pyrroles. Furthermore, 4-oxo-4H-chromene-3-carbonitrile (50) was also successfully utilized in this reaction, yielding the desired chromenone fused pyrrole derivative (51). Various functional groups were well tolerated under the optimized reaction conditions, enabling the synthesis of a diverse range of substituted pyrroles in very good yields. The authors have also provided a comparative study of solvents (DMSO and DMF. Additionally, the methodology was demonstrated on a gram scale, highlighting its practical applicability. Overall, this is a well-executed study, and the work can be accepted in Organic & Biomolecular.
1. Why was only ToSMIC used? Have the authors explored other isocyanides, such as ethyl or methyl isocyanoacetate?
2. Isocyanides sometimes dimerize to form imidazole as a side product. I wonder if the authors have observed this under the reported reaction conditions.
3. There are some typographical errors that the authors need to correct in the revised manuscript.