𝔖 Bobbio Scriptorium
✦   LIBER   ✦

Determination of the geometry of acetoxyendiynes and acetoxyenynes by NMR heteronuclear 13C1H scalar couplings and 13C NMR chemical shifts. Structural assignment of the oxylipin natural products peyssonenynes A and B

✍ Scribed by Patricia García; Manuel Martín-Pastor; Ángel R. de Lera; Rosana Álvarez

Publisher
John Wiley and Sons
Year
2010
Tongue
English
Weight
235 KB
Volume
48
Category
Article
ISSN
0749-1581

No coin nor oath required. For personal study only.

✦ Synopsis

Abstract

Solution NMR methods were used for the structural characterization of the acetoxyendiyne E/Z configuration of the marine natural products peyssonenynes A and B and their synthetic analogs derived from palmitic acid. The scarcity of protons in the proximity of the olefin precluded the determination of the double bond geometry using ^1^H NMR methods that rely on proton–proton scalar couplings or experiments such as NOESY or ROESY. Long range ^1^H^13^C heteronuclear scalar couplings, ^n^J~CH~, measured with the 2D excitation sculptured indirect detection experiment (EXSIDE) proved useful and highly reliable for the analysis of the enol acetate geometry. In addition, it was found that the chemical shift of some carbon atoms in the proximity of the olefin was also sensitive to the double bond configuration of these molecules providing an even simpler way to determine their geometry. This protocol showed its robustness by similar analysis of simpler silyl‐protected acetoxyenynes derived from fatty acids. These NMR experimental results and stereochemical predictions were rationalized by DFT calculations. Copyright © 2010 John Wiley & Sons, Ltd.

📜 SIMILAR VOLUMES

Total Assignment of the 1H and 13C NMR C
Total Assignment of the 1H and 13C NMR Chemical Shifts of Three Bisabolane Hydrocarbons by 2D-NMR Spectroscopy
✍ Lai-King Sy; Geoffrey D. Brown 📂 Article 📅 1997 🏛 John Wiley and Sons 🌐 English ⚖ 151 KB 👁 2 views

Three known bisabolane hydrocarbons, a-trans -bergamotene, sesquiphellandrene and zingiberene, were isolated from the aerial parts of Alpinia densibracteata . Their 1H and 13C NMR spectra were completely assigned by using a combination of 13C DEPT and 2D-NMR experiments (1H-1H COSY, single-bond 13C-

1H and 13C NMR chemical shift assignment
1H and 13C NMR chemical shift assignments of spiro-cycloalkylidenehomo- and methanofullerenes by the DFT–GIAO method
✍ L. M. Khalilov; A. R. Tulyabaev; V. M. Yanybin; A. R. Tuktarov 📂 Article 📅 2011 🏛 John Wiley and Sons 🌐 English ⚖ 353 KB

## Abstract The ^1^H and ^13^C NMR chemical shifts of __spiro__‐cycloalkylidene[60]fullerenes were assigned using experimental NMR data and the Density Functional Theory (DFT)–Gauge Independence Of Atomic Orbitals method (GAIO) calculation method in the Perdew Burke Ernzerhof (PBE)/3z approach. The

1H and 13C NMR spectral assignment of th
1H and 13C NMR spectral assignment of the prenylflavanones sigmoidins A, B and C, by two-dimensional NMR techniques
✍ Jean-Claude Ndom; J. Tanyi Mbafor; Z. Tanee Fomum; Marie-Thérèse Martin; Bernard 📂 Article 📅 1993 🏛 John Wiley and Sons 🌐 English ⚖ 163 KB 👁 1 views

## Abstract Three prenylflavanones, sigmoidins A, B and C, were studied using one‐ and two‐dimensional NMR techniques. The interpretation of these spectra led to the definitive assignments of all carbon and hydrogen chemical shifts.