ChemInform Abstract: Synthesis of Bis(indole) Alkaloids from Arundo donax: The Ynindole Diels—Alder Reaction, Conformational Chirality, and Absolute Stereochemistry.

Chen, Jingjin; Ferreira, Andrew J.; Beaudry, Christopher M.

doi:10.1002/chin.201514029

Cited by 1 publication

(2 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Recent applications of ECM to biaryl compounds include bis(indole) alkaloids 63 and BODIPY dimers, 64 , 65 though these latter are complicated by the fact that the major π–π* transition around 500 nm is also magnetically dipole allowed.…”

Section: Overview Of Selected Ecm Applicationsmentioning

confidence: 99%

“…The value assumed by the dihedral angle is the major factor influencing ECD spectra, and, conversely, ECD spectra are good reporters of the absolute geometry around that axis. 61,62 Recent applications of ECM to biaryl compounds include bis(indole) alkaloids 63 and BODIPY dimers, 64,65 though these latter are complicated by the fact that the major π-π* transition around 500 nm is also magnetically dipole allowed.…”

Section: Biaryls: 11 0 -Binaphthylsmentioning

confidence: 99%

See 1 more Smart Citation

ECD exciton chirality method today: a modern tool for determining absolute configurations

Pescitelli

2021

Chirality

View full text Add to dashboard Cite

The application of the exciton chirality method (ECM) to interpret electronic circular dichroism (ECD) spectra is a well-established and still popular approach to assign the absolute configuration (AC) of natural products, chiral organic compounds, and organometallic species. The method applies to compounds containing at least two chromophores with electric dipole allowed transitions (e.g., π-π* transitions). The exciton chirality rule correlates the sign of an exciton couplet (two ECD bands with opposite sign and similar intensity) with the overall molecular stereochemistry, including the AC. A correct application of the ECM requires three main prerequisites: (a) the knowledge of the molecular conformation, (b) the knowledge of the directions of the electric transition moments (TDMs), and (c) the assumption that the exciton coupling mechanism must be the major source of the observed ECD signals. All these prerequisites can be easily verified by means of quantum-mechanical (QM) calculations. In the present review, we shortly introduce the general principles that underpin the use of the ECM for configurational assignments and survey its applications, both classic ones and some reported in the recent literature. Based on these examples, we will stress the advantages of the ECM but also the key requisites for its correct application. Additionally, we will discuss the dependence of the couplet sign on geometrical parameters (angles α,β,γ between TDMs), which can be helpful for discerning the sign of exciton chirality in ambiguous situations. Finally, we will present a molecular orbital (MO) description of the exciton coupling phenomenon.

show abstract

Section: Overview Of Selected Ecm Applicationsmentioning

confidence: 99%