Lithium 2,3-dihydro-1-benzothiophene-1,1-dioxide: synthesis, characterization, DFT calculations, and reactivity toward aldehydes and azomethines

The sulfonyl carbanion derived from 2,3-dihydro-1-benzothiophene-1,1-dioxide and its lithium salt has been investigated by DFT calculations. NMR and IR spectroscopic analyses showed that the lithium sulfonyl carbanion exists in solution as a monomer in equilibrium with a dimer. The lithium carbanion was treated with aldehydes and azomethynes to give chiral hydroxy and amino derivatives. The stereochemistry of the products and the diastereoselectivity of the reaction were investigated.