Stereochemistry of Chiral 2-Substituted Chromanes: Twist of the Dihydropyran Ring and Specific Optical Rotation.
Molecules
; 28(1)2023 Jan 03.
Article
in En
| MEDLINE
| ID: mdl-36615631
ABSTRACT
Chiral 2-substituted chromanes are important substructures in organic synthesis and appear in numerous natural products. Herein, the correlation between specific optical rotations (SORs) and the stereochemistry at C2 of chiral 2-substituted chromanes was investigated through data mining, quantum-chemical calculations using density functional theory (DFT), and mechanistic analyses. For 2-aliphatic (including acyloxy and alkenyl) chromanes, the P-helicity of the dihydropyran ring usually corresponds to a positive SOR; however, 2-aryl chromanes with P-helicity tend to exhibit negative SORs. 2-Carboxyl (including alkoxycarbonyl and carbonyl) chromanes often display small experimental SORs, and theoretical calculations for them are prone to error because of the fluctuating conformational distribution with computational parameters. Several typical compounds were discussed, including detailed descriptions of the asymmetric synthesis, absolute configuration (AC) assignment methods, and systematic conformational analysis. We hope this work will enrich the knowledge of the stereochemistry of chiral 2-substituted chromanes.
Key words
Full text:
1
Database:
MEDLINE
Main subject:
Optical Rotation
Language:
En
Journal:
Molecules
Journal subject:
BIOLOGIA
Year:
2023
Type:
Article
Affiliation country:
China