Synthesis of 3,5-dialkyl-1,2,4-trithiolanes: Assignment of configuration and conformational analysis by PMR

摘要: Abstract 3,5-Dialkyl-1,2,4-trithiolanes (I–IV) have been synthesized in reasonable yields by a new route involving chlorination of dialkyl disulfides to α-chloroalkyl sulfenyl chlorides, reaction with potassium iodide giving di-α-chloroalkyl and subsequent cyclization sodium sulfide. All dialkyltrithiolanes exist two isomeric configurations ( cis/trans ), separable preparative GLC or column chromatography over alumina. We were able assign unequivocally the cis trans use Nuclear Overhauser Effect. From temperature dependence PMR spectra from Aromatic Solvent Induced Shifts it appeared that all show pseudorotation: relative abundance each conformer is dependent on bulk alkyl groups. The energy barrier for pseudorotation was estimated be smaller than 6 kcal/mole.