Zinc‐Catalyzed Functionalization of SiH Bonds with 2‐Furyl Carbenoids through Three‐Component Coupling

Abstract

A three-component coupling of alk-2-ynals, 1,3-dicarbonyls and silanes is reported. ZnCl2 serves as inexpensive and low-toxic catalyst for the overall transformation, which involves Knoevenagel condensation, cyclization and carbene Si-H bond insertion. The process takes place with atom economy in the absence of organic solvents and shows a broad scope. This reaction proves also applicable to the functionalization of oligomeric siloxanes.

Zinc‐Catalysed Multi‐Component Reactions: An Overview

“…Vicente and co‐workers have established a coupling between 1,3‐dicarbonyls, silanes and alk‐2‐ynals for the synthesis of furan derivatives . The reaction was effected by 5 mol % ZnCl 2 at 60 °C under neat conditions for 12–16 h (Scheme ).…”

Carbene X H bond insertions catalyzed by copper(I) macrocyclic pyridine-containing ligand (PcL) complexes

“…Neither the modifications on the arene of the diazo compounds nor the substituents on the silane showed a decisive influence in the stereochemical outcome of the reaction when L3 was used, providing low ee values (0-36% ee, see Supporting Information for details). In the recent years, the use of conjugated enynones as precursors of furyl carbene intermediates has been fruitfully exploited by means of transition metal catalysis [48][49][50] .…”

Zinc‐Catalyzed Multicomponent Reactions: Easy Access to Furyl‐Substituted Cyclopropane and 1,2‐Dioxolane Derivatives

“…As the enynone starting materials were prepared by conventional base‐promoted Knoevenagel condensation methodologies and zinc chloride catalyzes some of these condensation reactions,6 we realized that a sequence consisting of a zinc‐catalyzed Knoevenagel condensation followed by cyclization and a final cyclopropanation reaction would represent a convenient multicomponent catalytic approach to the final cyclopropane derivatives 7–9…”