Structure elucidation with lanthanide-induced shifts. 15. Blocking groups for polyfunctional compounds

Abstract

This article assesses the effectiveness of silyl ethers as blocking groups for hydroxyl groups in shift reagent work. The chemical preparation and study of derivatives of a series of monofunctional alcohols was undertaken to analyze the molecular structure with lanthanide shift reagents (LSR). Evaluation of derivatives of primary, secondary, and tertiary alcohols were undertaken. Results indicated that the effectiveness at preventing coordination with LSR and the remarkable ease with which this blocking group can be introduced and removed combine to make tert-butyldimethylsilyl ethers the derivatives of choice for shift reagent studies. Results demonstrate that tert-butyldimethylsilyl ethers allow, for the first time, the use of lanthanide shift reagents for reliable and accurate structure evaluation of polyfunctional organic compounds.