The Wittig reaction is one of the most important processes in organic chemistry for the asymmetric synthesis of olefinic compounds. In view of the increasingly acknowledged potentiality of the electric fields in promoting reactions, here we will consider the effect of the oriented external electric field (OEEF) on the second step of Wittig reaction (i. e. the ring opening oxaphosphetane) in a model system for non-stabilized ylides. In particular, we have determined the optimal direction and strength of the electric field that should be applied to annihilate the reaction barrier of the ring opening through the polarizable molecular electric dipole (PMED) model that we have recently developed. We conclude that the application of the optimal external electric field for the oxaphosphetane ring opening favours a Bestmann-like mechanism.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1002/chem.202400173 | DOI Listing |
Angew Chem Int Ed Engl
January 2025
Westlake University, Chemistry, No.18 Shilongshan Road, 310024, Hangzhou, CHINA.
Efficient methods for synthesizing allenes from readily available starting materials pose a persistent challenge in organic chemistry. In this work, we present a novel two-stage protocol for allene synthesis involving the single-atom insertion into alkenes, facilitated by synergistic photoredox and cobalt catalysis. Diverging from conventional methods such as the Doering-LaFlamme reaction, this photochemical rearrangement approach operates efficiently under mild conditions in a radical-based manner.
View Article and Find Full Text PDFBiomaterials
January 2025
Department of Laboratory Medicine and Department of Ultrasound, Sichuan Academy of Medical Sciences, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, No. 32, West Second Section, First Ring Road, Chengdu, 610072, Sichuan, China. Electronic address:
Incomplete radiofrequency ablation (iRFA) not only leaves residual tumor, but also render the residual tumor highly self-adaptable and immunosuppressive, consequently expediting residual tumor progression including relapse. To address it, radiofrequency dynamic therapy (RFDT) with identical trigger (namely radiofrequency) has been established and enabled by polyethylene glycol (PEG)-modified Fe-based single atom nanozyme (P@Fe SAZ). P@Fe SAZ can respond to radiofrequency field to produce reactive oxygen species (ROS), attaining the nanomedicine-unlocked low-temperature RFDT.
View Article and Find Full Text PDFChemistry
January 2025
University of Regensburg, Inorganic Chemistry, Universitätsstrasse 31, D-93040, Regensburg, GERMANY.
The systematic nucleophilic functionalization of the cationic pentaphosphole ligand complex [Cp*Fe(η4-P5Me)][OTf] (A) with group 16/17 nucleophiles is reported. This method represents a highly reliable and versatile strategy for the design of novel transition-metal complexes featuring twofold substituted end-deck cyclo-P5 ligands, bearing unprecedented hetero-element substituents. By the reaction of A with classical group 16 nucleophiles, complexes of the type [Cp*Fe(η4-P5MeE)] (E = OEt (1), OtBu (2), SPh (3), SePh (4)) are obtained.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
New York University, Chemistry, 29 Washington Place, RM 10001, 10003, New York, UNITED STATES OF AMERICA.
Herein, we report a Lewis acid-mediated ring expansion of donor-acceptor cyclopropanes (DACs) to substituted azetidines via nucleophilic nitrogen group transfer from readily accessible iminoiodinane. This protocol operates under mild, transition-metal-free conditions, and showcases excellent chemoselectivity, along with broad functional group tolerance. We report for the first time that challenging alkyl donor-acceptor cyclopropanes can undergo ring expansion leading to aliphatic azetidines without relying on external oxidants or precious transition-metal catalysts.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
South China University of Technology, Faculty of Materials Science and Engineering, 381 Wushan Road, 510641, Guangzhou, CHINA.
Amide groups occur extensively in natural and synthetic polymers cultivating their vital roles in biological and industrial worlds. We report here an efficient and controlled pathway to amide-functionalized polyethers through ring-opening polymerization (ROP) of commercially available ethyl glycidate followed by amidation of the pendant ester groups. Transesterification is inhibited during the ROP by use of a two-component organocatalyst.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!