Dealkenylative Alkenylation: Formal σ‐Bond Metathesis of Olefins

Abstract

The dealkenylative alkenylation of alkene C(sp3)−C(sp2) bonds has been an unexplored area for C−C bond formation. Herein 64 examples of β‐alkylated styrene derivatives, synthesized through the reactions of readily accessible feedstock olefins with β‐nitrostyrenes by ozone/FeII‐mediated radical substitutions, are reported. These reactions proceed with good efficiencies and high stereoselectivities under mild reaction conditions and tolerate an array of functional groups. Also demonstrated is the applicability of the strategy through several synthetic transformations of the products, as well as the syntheses of the natural product iso‐moracin and the drug (E)‐metanicotine.

Dealkenylative Functionalizations: Conversion of Alkene C(sp3)–C(sp2) Bonds into C(sp3)–X Bonds via Redox-Based Radical Processes

“…The first example of this type of C–C bond formation was dealkenylative alkenylation (Figure 11 ). 12 Alkene formation is important in organic synthesis because olefins are among the most versatile synthetic intermediates. 1 Early olefinations from alkyl radicals relied on β-hydride elimination using a copper(II) species, as demonstrated by De La Mare–Kochi–Rust.…”

“…Gratifyingly, methods have been developed recently to strategically cleave alkenyl C(sp 3 )–C(sp 2 ) σ-bonds to expand the existing potential of olefinic compounds. Indeed, several examples of fragmenting these ‘inert’ bonds and installing useful synthetic motifs in their wake—including C(sp 3 )–H, 8 9 C(sp 3 )–S, 10 C(sp 3 )–O, 11 C(sp 3 )=O, 11 C(sp 3 )–C(sp 2 ), 12 and C(sp 3 )–C(sp) 13 functionalities—have been explored since 2018.…”

“…Using terpenes and terpenoids from Nature’s chiral pool allows the rapid derivatization of feedstock olefins into enantiopure terpene derivatives that are relevant synthetically. For example, many natural products 3 9 12 15 16 and chiral phosphine catalysts 8 have been synthesized efficiently and selectively using this approach. Overall, dealkenylative functionalization is a powerful method that allows synthetic chemists to take advantage of ubiquitous alkenes and provides access to unprecedented building blocks from Nature.…”

Constructive Ozonolysis: Capturing Primary Ozonides

“…Pioneered by Schreiber (5), the use of additives after carbon-carbon (C-C) bond cleavage extended the realm of deconstructive ozonolysis procedures to include synthetic access to acetals, esters, and on occasion elaborated olefins (Fig. 1A) (6)(7)(8)(9)(10)(11). While breaking C-C bonds in olefins has been beneficial and well established in ozonolysis, it is the construction of bonds that leads to higher molecular complexity and is the goal of modern synthesis.…”