Metal‐Catalyzed Remote Functionalization of ω‐Ene Unsaturated Ethers: Towards Functionalized Vinyl Species

Abstract

The combined ruthenium-catalyzed chain walking with the nickel-catalyzed cross-coupling reaction of ω-alkenyl ethers provide a unique entry to functionalized vinyl species. This transformation illustrates the power and flexibility of remote functionalization by demonstrating the compatibility of two independent reactions involving unrelated sites.

Transition metal-catalyzed alkene isomerization as an enabling technology in tandem, sequential and domino processes

“…Concomitantly, the Marek group reported a complementary [Ru/Ni] catalytic combination for the remote isomerization/ cross-coupling of alkenyl benzyl-, silyl-, methoxyethoxy-methyl ethers leading to 1,2-disubstituted alkenes (37). 54 While the isomerization was performed in refluxing THF, addition of toluene was found to be beneficial for the cross-coupling reaction (1 : 1 v/v). Only C(sp 2 ) Grignard reagents were disclosed, and higher levels of stereocontrol were achieved in comparison with the [Pd/Ni] system (1 : 1 to 19 : 1).…”

Ru-catalyzed isomerization of ω-alkenylboronates towards stereoselective synthesis of vinylboronates with subsequent in situ functionalization

“…combination enabled a highly E-selective cross-coupling reaction of the in situ generated (E)-vinylboronates that was not possible to get with our previous procedure on u-alkenyl ethers. 11,12 Various aryl halides and alkenyl triate were compatible furnishing the coupling products 3a-f in satisfying yields (based on two chemical steps) with excellent E : Z ratios.…”

“…However, the preparation of a distant functionalized alkenyl organometallic species from an original sp 3 carbon center remains less explored (Scheme 1a, path b). 2g In this regard, we 11 and Mazet 12 have independently reported an efficient Pd-Ni and Ru-Ni double catalytic system transforming readily available u-alkenyl ethers into a large variety of styrenyl products (Scheme 1b). Despite these signicant advances, several challenges remain to be addressed such as the moderate level of stereocontrol over the geometry of the formed enol ether as well as the low E/Z-selectivity of the nal cross-coupled products.…”

Migratory functionalization of unactivated alkyl bromides for construction of all-carbon quaternary centers via transposed tert-C-radicals

“…By exploiting iterative hydrometallation and β-hydride elimination, chain-walking enables the site-selective cross-coupling at positions remote to the initial metallation site 33,34 . Owing to the efforts of Sigman [35][36][37] , Marek [38][39][40] , Mazet [41][42][43] , Martín [44][45][46][47] , Zhu [48][49][50][51][52][53][54][55][56][57] , and others [58][59][60][61][62][63][64][65][66] , a collection of remote functionalizations, including arylation, alkylation, carboxylation, amination, borylation, and thiolation of unactivated alkenes or alkyl halides have been developed. Very recently, our team leveraged the fluorine-effect for a remote fluoro-alkenylation of unactivated alkyl bromides (Fig.…”