H-1 chemical shift differences of Prelog-Djerassi lactone derivatives: DFT and NMR conformational studies

Author(s)

Aimola, Tulio J. ^{[1, 2]} ; Lima, Dimas J. P. ^{[3, 4]} ; Dias, Luiz C. ^[4] ; Tormena, Claudio F. ^[4] ; Ferreira, Marco A. B. ^{[1, 2]}

Affiliation

^[1] Univ Fed Sao Carlos, Lab Quim Bioorgan, BR-13560 Sao Carlos, SP - Brazil

^[2] Univ Fed Sao Carlos, Lab Cristalog Estereodinam & Modelagem Mol, BR-13560 Sao Carlos, SP - Brazil

^[3] Univ Estadual Campinas, Inst Chem, BR-13084971 Campinas, SP - Brazil

^[4] Univ Fed Alagoas, BR-57072900 Maceio - Brazil

• Document type: Journal article
• Source: ORGANIC & BIOMOLECULAR CHEMISTRY; v. 13, n. 7, p. 2140-2145, 2015.
• Web of Science Citations: 4

Abstract

This work reports an experimental and theoretical study of the conformational preferences of several Prelog-Djerassi lactone derivatives, to elucidate the H-1 NMR chemical shift differences in the lactonic core that are associated with the relative stereochemistry of these derivatives. The boat-like conformation of 2 explains the anomalous H-1 chemical shift between H-5a and H-5b, in which the two methyl groups (C-8 and C-9) face H-5b, leading to its higher shielding effect. (AU)

• FAPESP's process: 13/02311-3 - New approaches in asymmetric synthesis of tetrahydrofuran and tetrahydropyran-derivatives with potential application in the preparation of bioactive molecules
• Grantee: Marco Antonio Barbosa Ferreira
• Support Opportunities: Regular Research Grants