Decarboxylative 1,3-dipolar cycloaddition of amino acids for the synthesis of heterocyclic compounds

• Xiaofeng Zhang,
• Xiaoming Ma and
• Wei Zhang

Beilstein J. Org. Chem. 2023, 19, 1677–1693, doi:10.3762/bjoc.19.123

•  6) [75]. One-pot double annulations for the synthesis of tetrahydropyrrolothiazoles The unique tetrahydropyrrolothiazole and spiro[indole-tetrahydropyrrolothiazole] scaffolds are found in bioactive compounds such as those shown in Figure 7 [76][77]. Using cysteine as a key reactant, we developed a

One-pot double annulations to confer diastereoselective spirooxindolepyrrolothiazoles

• Juan Lu,
• Bin Yao,
• Desheng Zhan,
• Zhuo Sun,
• Yun Ji and
• Xiaofeng Zhang

Beilstein J. Org. Chem. 2022, 18, 1607–1616, doi:10.3762/bjoc.18.171

• oxindoles. High synthetic efficiency, operational simplification and reaction process economy using EtOH as solvent, and only releasing CO2 and H2O as side products confer this approach favorable in green chemistry metrics analysis. Keywords: azomethine ylides; cascade; double annulations; N,S-acetalation

• PASE reactions of making spirooxindolepyrrolothiazoles are even more rare, which only involves three-component reactions with isatins and thioproline (Scheme 2A and 2B) [75][76]. Four-component double annulations through 2-substituted thioprolines formed in N,S-acetalation of aldehyde and cysteine was

• -component reaction (4-CR) with 2.2:1.1:1.0 of 1a/2/4a at 90 °C for 9 h in EtOH after variations of solvents, reaction time and temperature with one operational step (Table 1, entries 7–12). This 4-CR is the first example of double annulations with sequential N,S-acetalation and [3 + 2] cycloaddition for