Iron‐Catalyzed Radical Cleavage/C−C Bond Formation of Acetal‐Derived Alkylsilyl Peroxides

Abstract

A novel radical‐based approach for the iron‐catalyzed selective cleavage of acetal‐derived alkylsilyl peroxides, followed by the formation of a carbon–carbon bond is reported. The reaction proceeds under mild reaction conditions and exhibits a broad substrate scope with respect to the acetal moiety and the carbon electrophile. Mechanistic studies suggest that the present reaction proceeds through a free‐radical process involving carbon radicals generated by the homolytic cleavage of a carbon–carbon bond within the acetal moiety. A synthetic application of this method to sugar‐derived alkylsilyl peroxides is also described.

Methylene-Bridged Dimerization by Cu-Catalyzed Deconstructive C–C Cleavage of Oxacycloalkane

“…Based on our experiments and literature reports, ,, a plausible mechanism for the formation of the methylene-bridged dimers c/d is depicted in Scheme . This process is likely a Cu-catalyzed autoxidation reaction.…”

Synthesis of Functionalized Aliphatic Acid Esters via the Generation of Alkyl Radicals from Silylperoxyacetals

“…Using these methods, a variety of functional groups can be introduced to the in situ generated alkyl radicals, which have a terminal keto group, to provide the corresponding aliphatic ketone derivatives. In addition, we have prepared acetal‐derived alkylsilyl peroxides from sugar derivatives [6f] . These compounds can be transformed into polyoxygenated linear formyl esters via an iron‐catalyzed C−C bond cleavage/C−C bond formation sequence.…”

“…Thus, we attempted to construct the substructure of a potent thromboxane A 2 (TXA 2 )‐receptor antagonist (Figure 1) using an iron‐catalyzed radical addition to the corresponding diarylethylene (Scheme 3). [6f] Starting from a silylperoxyacetal containing a five‐membered ring ( 1 b ), the reaction with diarylethylene 10 in the presence of a catalytic amount of FeCl 3 gave the desired alkene 11 in good yield as a mixture of E and Z isomers. The isomers were reduced efficiently using a catalytic amount of palladium on carbon under an atmosphere of hydrogen gas to furnish 1,1‐diarylalkane 12 .…”

The Formation of C–C or C–N Bonds via the Copper-Catalyzed Coupling of Alkylsilyl Peroxides and Organosilicon Compounds: A Route to Perfluoroalkylation

“…However, despite its long history, radical chemistry remains relatively underdeveloped. Recently, we have reported a series of radical-mediated synthetic transformations based on the homolytic cleavage of alkylsilyl peroxides catalyzed by copper, − nickel, and iron , salts. These synthetic transformations allowed the facile amidation, amination, acyloxylation, borylation, silylation, alkylation, ,, arylation, , and alkynylation of intermediary carbon radicals generated in situ from alkylsilyl peroxides.…”

“…Recently, we have reported a series of radical-mediated synthetic transformations based on the homolytic cleavage of alkylsilyl peroxides catalyzed by copper, − nickel, and iron , salts. These synthetic transformations allowed the facile amidation, amination, acyloxylation, borylation, silylation, alkylation, ,, arylation, , and alkynylation of intermediary carbon radicals generated in situ from alkylsilyl peroxides. In addition to these synthetic transformations, the development of simple yet useful functional group transformations for in situ generated radical species is also an important issue in this field .…”