Toward Consistent Terminology for Cyclohexane Conformers in Introductory Organic Chemistry

Abstract

Recommended changes in use of cyclohexane conformers and their nomenclature will remedy inconsistencies in cyclohexane conformers and their nomenclature that exist across currently used organic chemistry textbooks. These inconsistencies prompted this logical analysis and the resulting recommendations. Recommended conformer names are chair, half-chair, twist-boat, and boat. These names are frequently used, although usually combined with additional or alternate names that can confuse students consulting multiple textbooks. The half-chair conformation structure with four coplanar carbons is recommended instead of the structure with five coplanar carbons, because calculations predict it is more stable and lies on the lowest energy pathway for cyclohexane conformer interconversion. Currently, the incorrect structure with five coplanar carbons is most often presented to students. As defined, the recommended names and structures are consistent, descriptive, pedagogically useful, and in agreement with research literature.