ABSTRACT
A formal thio [3 + 3]-cyclization catalyzed by a DPEN-derived chiral thiourea has been reported for the construction of optically active thiopyrano-indole annulated heterocyclic compounds in high yields with excellent enantioselectivities. The high reactivity between indoline-2-thione (keto-S) and 2-benzylidenemalononitrile has also been supported by density functional theory (DFT) calculations.
Subject(s)
Heterocyclic Compounds, 4 or More Rings/chemical synthesis , Indoles/chemistry , Cyclization , Ethylenediamines/chemistry , Heterocyclic Compounds, 4 or More Rings/chemistry , Stereoisomerism , Thiourea/chemistryABSTRACT
Enantioselective phosphination and hydrophosphonylation reactions between azomethine imines and diarylphosphine oxides or dialkyl phosphites were respectively developed by the use of a chiral squaramide as the hydrogen bonding organocatalyst, which afforded two types of phosphorus containing product in high yields with good to excellent enantioselectivities.