Mechanistic Insights into an Unexpected Carbon Dioxide Insertion Reaction through the Crystal Structures of Carbamic Diphenylthiophosphinic Anhydride and l-[(4-Nitrophenyl)-sulfonyl]-trans-2,5-pyrrolidinedicarboxylic Acid Methyl Ester

The crystal structures of an unexpected carbon dioxide inserted carbamidiphenylthiophosphinic anhydride and l-[(4-nitrophenyl) sulfonyl]-trans-2, 5-pyrrolidinedicarboxylic acid methyl ester were determined by X-ray analysis. They crystallized in the space group P2₁(#4) with a =0.9550(2), b = 0.9401(4), c= 1.2880(2) nm, β= 107.74°, V= 1.1013 (5) nm³, D_caled= 1.349 g/cm³, Z = 2 and P2₁2₁2₁(# 19) with a = 1.4666(2), b = 0.7195(2), c = 1.6339(2) nm, V = 1.7240(7) nm³, D_caled = 1.434 g/cm³, Z = 4, respectively. Through the investigation of these two crystal structures, the mechanistic insights into this unexpected carbon dioxide insertion in the reaction of trans-2,5-disubstituted pyrrolidine with diphenylthiophosphoryl chloride in the presence of potassium carbonate were disclosed.