Non-peripherally substituted metallophthalocyanines catalyzed diastereoselective carbonyl-ylide reactions: Synthesis and DFT calculations

Many catalysts are used to control the chemo-selectivity, diastereoselectivity, and enantioselectivity in carbenoid reactions. In this work, the [4 + 1] carbonyl-ylide reaction of dimethyl diazomalonate with α-ionone and the [3 + 2] carbonyl-ylide reaction of dimethyl diazomalonate with thiophene-2-carbaldehyde were chosen to obtain enriched diastereomeric products with the synthesized metallophthalocyanine compounds as catalysts. Four metallophthalocyanines (MPcs) including two neopenthoxy substituted and two novel fenchoxy substituted on non-peripheral positions of phthalocyanine ring were synthesized. Their catalytic activities were also compared with several common catalysts. Our results showed that in both reactions copper-Pc with neopentyl is the most effective catalyst to obtain diastereoselective results with diastereomeric product ratios of 30:70 and 10:90. DFT calculations also performed to explain the effect of the catalyst in diastereoselectivity. The calculations were in good agreement with the experimental results and assisted in understanding the selectivity.