A New, Convenient Method for Labeling Cyclopentadienyl Ligands with Deuterium

Base-Mediated Deuteration of Organic Molecules: A Mechanistic Insight

A base-promoted, step-economical, and cost-effective strategy for introducing heavy isotopes into the organic molecules has been developed. The schemes involve the selective deuteration of various electronically distinct molecules that are formed because of deuterioamination, deuteriothiolation, deuteriophenoxylation, and deuterioalkoxylation as well as tandem cyclization using dimethyl sulfoxide (DMSO)-d ₆ as a deuterium source. The reaction involves a metal-, ligand-, and additive-free route and provides a high level of deuterium incorporation in the presence of DMSO-d ₆ as an inflammable and ecological reagent. The reaction is well tolerated across the electronically varied substrates for the successful incorporation of deuterium into the product. The proposed mechanistic pathway for various transformations has been well supported by NMR studies.

The renaissance of H/D exchange

The increasing demand for stable isotopically labeled compounds has led to an increased interest in H/D-exchange reactions at carbon centers. Today deuterium-labeled compounds are used as internal standards in mass spectrometry or to help elucidate mechanistic theories. Access to these deuterated compounds takes place significantly more efficiently and more cost effectively by exchange of hydrogen by deuterium in the target molecule than by classical synthesis. This Review will concentrate on the preparative application of the H/D-exchange reaction in the preparation of deuterium-labeled compounds. Advances over the last ten years are brought together and critically evaluated.