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The carbon‐carbon (C—C) σ‐bonds construct the fundamental frameworks of organic molecules. The direct functionalization of C—C bonds represents one of the most efficient and step‐economical transformations in synthetic chemistry. The past few decades have witnessed the fast development of transition‐metal mediated C—C bond activation. In contrast, the radical‐promoted C—C bond cleavage has received relatively less attention. As the occurrence of ring strain significantly facilitates the fission of cyclic C—C bonds via radical approaches, the strain relief‐driven C—C bond activation mostly relies on the three‐ and four‐membered rings. The C—C activation of non‐strained molecules such as medium‐ or large‐sized rings and linear alkanes remains challenging. In this review, we will focus on the recent advances in radical‐mediated C—C bond activation of non‐strained molecules. Herein, the alkoxy‐ and iminyl‐radical triggered scission of non‐strained C—C bonds and C—C cleavage via the strategy of remote functional group migration is summarized. The recent advances in radical‐mediated C—C bond activation of non‐strained molecules are summarized in this review. These transformations are mainly accomplished during the past three years, thus representing an emerging topic in organic chemistry. The alkoxy‐ and iminyl‐radical triggered cleavage of non‐strained C—C bonds and the C—C activation via the strategy of remote functional group migration are discussed in details. [ABSTRACT FROM AUTHOR]

Abstract: Cycloalkanols prove to be privileged precursors for the synthesis of distally substituted alkyl ketones and polycyclic aromatic hydrocarbons (PAHs) by virtue of cleavage of their cyclic C−C bonds. Direct functionalization of cyclobutanols to build up other chemical bonds (e. g., C−F, C−Cl, C−Br, C−N, C−S, C−Se, C−C, etc.) has been achieved by using the ring‐opening strategy. Mechanistically, the C−C cleavage of cyclobutanols can be involved in two pathways: (a) transition‐metal catalyzed β‐carbon elimination; (b) radical‐mediated ‘radical clock’‐type ring opening. The recent advances of our group for the ring‐opening functionalization of tertiary cycloalkanols are described in this account. [ABSTRACT FROM AUTHOR]

Disclosed herein is a novel, redox-neutral protocol for the visible-light-induced radical alkynylation of unactivated olefins. The intramolecular migration of an alkynyl group, by cleaving an inert C−C σ bond, is realized for the first time. A wide range of synthetically useful trifluoroethylated linear alkynes are readily obtained under mild reaction conditions. [ABSTRACT FROM AUTHOR]

The first iridium-catalyzed intermolecular cyclization between alkynes and ring-fused benzocyclobutenols (RBCB) through C--C bond cleavage is described. A variety of elusive polycyclic aromatic hydrocarbons (PAHs) with multiple substituents are obtained in good yields under mild conditions. This procedure provides a unique and expeditious tool for the synthesis of PAHs. [ABSTRACT FROM AUTHOR]

A novel, manganese-catalyzed oxidative azidation of cyclobutanols is described. A wide range of primary, secondary, and tertiary alkyl azides were generated in synthetically useful yields and exclusive regioselectivity. Aside from linear alkyl azides, otherwise elusive medium-sized cyclic azides were also readily prepared. Preliminary mechanistic studies reveal that the reaction likely proceeds by a radical-mediated CC bond cleavage/CN3 bond formation pathway. [ABSTRACT FROM AUTHOR]

Review: [57 refs. [ABSTRACT FROM AUTHOR]

A diverse range of primary or secondary alkyl thioethers is prepared in a scalable manner. [ABSTRACT FROM AUTHOR]

A unique and expeditious method for the synthesis of polycyclic aromatic hydrocarbons (26 examples) is developed using an unprecedented Ir-catalyzed intermolecular cyclization of alkynes with ring-fused benzocyclobutenols (I). [ABSTRACT FROM AUTHOR]

A graphical abstract of the article "Regiospecific Synthesis of Distally Chlorinated Ketones via C-C Bond Cleavage of Cycloalkanols" is presented.