The mechanisms of gallium-catalysed skeletal rearrangement of 1,6-enynes - Insights from quantum mechanical computations.

J Mol Graph Model

Theoretical and Computational Chemistry Laboratory, Department of Chemistry, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana. Electronic address:

Published: January 2020

AI Article Synopsis

  • The skeletal reorganization of 1,6-enynes leads to three product types: type I from alkene C-C bond cleavage and carbon migration, type II from breaking both alkene and alkyne bonds, and type III from olefin bond cleavage resulting in new bonds to acetylenic carbons.
  • This study, focusing on reactions catalyzed by GaCl, shows type I product formation as the primary outcome, influenced by the presence of electron-withdrawing (EWGs) or electron-donating groups (EDGs) on the substrates.
  • Substituents at the alkyne affect metal positioning and product distribution, with EWGs promoting type I and certain olefinic substitutions steering toward type

Article Abstract

The transition metal-catalysed skeletal reorganization of 1,6-enynes can lead to three types of products - a type I product occurring via the cleavage of the alkene C-C bonds and the migration of the terminal alkene carbon to the terminus of the alkyne; a type II product arising from cleavage of both the double and the triple bonds followed by insertion of the terminal alkene carbon into the alkyne C-C triple bond; and a type III product which is obtained when there is a cleavage of the olefinic bond followed by formation of two new bonds from each carbon to each of the acetylenic carbons. The course of these reactions is highly dependent on the metal catalyst used and type of substitution at the alkene and alkyne moieties of the enyne. In this mechanistic study of the re-organization of 1,6-enynes catalysed by GaCl, performed at the DFT M06/6-311G(d,p) level of theory, the parent reaction selectively leads to the formation of the type I product through the formation of the open cyclopropane ring. The presence of substituents at the acetylenic moiety governs the preferred position of the metal along the alkyne bond within the pi-complex: with electron-withdrawing groups (EWGs), the metal prefers the terminal carbon while electron-donating groups (EDGs) lead to the metal preferring the internal carbon. EWGs at the alkyne moiety efficiently favour the formation of the type I product. Substituents at the olefin moiety alter the mechanism of the reaction which may favour the selective formation of the type I or III product depending on the type of substituent. EWGs at the olefinic moiety favour formation of the type III product when the alkyne moiety is unsubstituted whiles EDGs forms the type I product selectively. Solvent and temperature have no substantial effects on the energetic trends and product distribution. Hence, gas-phase calculations are deemed adequate for the problem at hand.

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jmgm.2019.107476DOI Listing

Publication Analysis

Top Keywords

type product
20
formation type
16
type iii
12
iii product
12
type
10
product
9
terminal alkene
8
alkene carbon
8
alkyne moiety
8
favour formation
8

Similar Publications

Introduction: Two phase 3 randomized controlled studies (ADJUNCT ONE (Clinicaltrials.gov: NCT01836523), ADJUNCT TWO (Clinicaltrials.gov: NCT02098395)) evaluated liraglutide (1.

View Article and Find Full Text PDF

Placental trophoblasts constitute the interface between the fetal and maternal environments and physically prevent maternal-fetal viral transmission. However, congenital human cytomegalovirus (HCMV) infection in the early stages of pregnancy results in severe symptoms in the fetus. HCMV is the most common causative agent of intrauterine infection.

View Article and Find Full Text PDF

Assessment of azithromycin-induced toxicity in : Effects on morphology, behavior, and lipid metabolism.

Toxicol Rep

December 2024

Laboratory of Forensic Chemistry and Toxicology, School of Forensic Sciences, National Forensic Sciences University, Delhi, India.

Antibiotics are indispensable in modern healthcare, playing a critical role in mitigating bacterial infections. Azithromycin is used to fight upper respiratory tract infections, however has potential toxic effects that remain inadequately understood. In our present study, azithromycin exposure to led to significant physiological and behavioral change, with pronounced effects observed at the studied concentration.

View Article and Find Full Text PDF

Introduction: T-cadherin, a non-canonical member of the cadherin superfamily, was initially identified for its involvement in homophilic recognition within the nervous and vascular systems. Apart from its adhesive function, T-cadherin acts as a receptor for two ligands: LDL, contributing to atherogenic processes, and HMW adiponectin, a hormone with well-known cardiovascular protective properties. However, the precise role of T-cadherin in adipose tissue remains elusive.

View Article and Find Full Text PDF

Tunable band alignment and large power conversion efficiency in a two-dimensional InS/ZnInS heterostructure.

RSC Adv

December 2024

Chongqing Key Laboratory of Micro & Nano Structure Optoelectronics, School of Physical Science and Technology, Southwest University Chongqing 400715 China

Heterostructures can efficiently modulate the bandgap of semiconductors and enhance the separation of photocarriers, thereby enhancing the performance of optoelectronic devices. Herein, we design an InS/ZnInS van der Waals (vdW) heterostructure and investigate its electronic and photovoltaic properties using first principles calculation. Compared to its individual monolayers, the InS/ZnInS heterostructure not only possesses a smaller band gap of 2.

View Article and Find Full Text PDF

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!

A PHP Error was encountered

Severity: Notice

Message: fwrite(): Write of 34 bytes failed with errno=28 No space left on device

Filename: drivers/Session_files_driver.php

Line Number: 272

Backtrace:

A PHP Error was encountered

Severity: Warning

Message: session_write_close(): Failed to write session data using user defined save handler. (session.save_path: /var/lib/php/sessions)

Filename: Unknown

Line Number: 0

Backtrace: