Related Experiment Video
Updated: Sep 15, 2025

Efficient Synthesis of All-Carbon Quaternary Centers via the Conjugate Addition of Functionalized Monoorganozinc Bromides
Published on: May 26, 2019
Carbon Diarylation of Iodonium Ylides for Construction of All-Carbon Quaternary Centers
Chenggang Mi1, Deen Duan1, Zhaofeng Wang1
1State Key Laboratory of Chemo and Biosensing, College of Chemistry and Chemical Engineering, Hunan University, Changsha, Hunan 410082, People's Republic of China.
Abstract:
The construction of all-carbon quaternary centers via multiple bond formations remains a significant challenge in synthetic chemistry. Herein, we report a tandem diarylation process initiated via [2 + 2] cycloaddition between aryne species and iodonium ylides to form four-membered iodocyclobutane intermediate. This intermediate subsequently undergoes 1,2-aryl migration from iodonium to carbon, producing unsymmetrical α-diarylated malonic esters. The process is remarkable for its mild conditions, broad substrate compatibility, and capability to form two C-C bonds and one C-I bond in a single step. This work also uncovers a novel reaction mode for iodonium ylide reagents.
Related Concept Videos
Diazonium Group Substitution with Halogens and Cyanide: Sandmeyer and Schiemann Reactions
Electrophilic 1,2- and 1,4-Addition of X2 to 1,3-Butadiene
Carbocations
Diazonium Group Substitution: –OH and –H
[4+2] Cycloaddition of Conjugated Dienes: Diels–Alder Reaction
Electrophilic Addition to Alkynes: Halogenation
Halogenation is another class of electrophilic addition reactions where a halogen molecule gets added across a π bond. In alkynes, the presence of two π bonds allows for the addition of two equivalents of halogens (bromine or chlorine). The addition of the first halogen molecule forms a trans-dihaloalkene as the major product and the cis isomer as the minor product. Subsequent addition of the second equivalent yields the tetrahalide.

