Site-selective alkene borylation enabled by synergistic hydrometallation and borometallation

Iron‐Catalyzed Regioselective Alkenylboration of Olefins

“…Control experiments were performed to gain more insights into the mechanistic underpinnings of the Fe‐catalyzed alkenylboration (Scheme 4). As depicted in Scheme 4 A, deuteroboration of E ‐β‐methylstyrene ( E ‐ 6 ) under analogous conditions using MeOD in the absence of the alkenyl halide furnished the expected syn ‐addition product 7 in 79 % yield and >98 % diastereospecificity (residual protoboration adduct arising from adventitious t ‐BuOH formed by deprotonation of DMA with base [5] also detected). Consistent with our previous study, [5] this implies that an in situ‐generated iron‐boryl species selectively adds across the π‐bond in a syn fashion to form the putative intermediate III (cf.…”

“…Our interest in organoiron catalysis [5] led us to speculate if earth‐abundant iron‐based complexes [6] could serve as effective catalysts to promote alkene carboboration [7] . Specifically, we sought to design a single‐catalyst manifold that efficiently merges terminal olefins (without directing groups) [8] with bis(pinacolato)diboron and an alkenyl halide (Scheme 1 B), as a complementary method to previous Ni‐catalyzed reports where diminished yields and/or regioselectivity were observed with certain olefin substrates [2k,m] .…”

Secondary Phosphine Oxide-Activated Nickel Catalysts for Site-Selective Alkene Isomerization and Remote Hydrophosphination

“…If successfully obtained, the -branched alkylphosphine oxides not only function as stable precursors of the oxidation-labile phosphines [49][50][51] , but are also useful as Lewis bases [52][53][54] and ligands in organometallic chemistry [35][36][37][38][39][40][41][42] . To the best of our knowledge, there is no precedence of remote alkene hydrophosphination in which the phosphinyl unit is installed at less-reactive sites vicinal () to a pendant entity 9 . This will open up unexplored avenues towards the preparation of novel organophosphorus compounds for diverse applications such as drug synthesis 55,56 and ligand design 57,58 .…”

Iron‐Catalyzed Regioselective Alkenylboration of Olefins

“…Control experiments were performed to gain more insights into the mechanistic underpinnings of the Fecatalyzed alkenylboration (Scheme 4). As depicted in Scheme 4 A, deuteroboration of E-b-methylstyrene (E-6) under analogous conditions using MeOD in the absence of the alkenyl halide furnished the expected syn-addition product 7 in 79 % yield and > 98 % diastereospecificity (residual protoboration adduct arising from adventitious t-BuOH formed by deprotonation of DMA with base [5] also detected). Consistent with our previous study, [5] this implies that an in situ-generated iron-boryl species selectively adds across the p-bond in a syn fashion to form the putative intermediate III (cf.…”

“…Our interest in organoiron catalysis [5] led us to speculate if earth-abundant iron-based complexes [6] could serve as effective catalysts to promote alkene carboboration. [7] Specifically, we sought to design a single-catalyst manifold that efficiently merges terminal olefins (without directing groups) [8] with bis(pinacolato)diboron and an alkenyl halide (Scheme 1 B), as a complementary method to previous Ni-catalyzed reports where diminished yields and/or regioselectivity were observed with certain olefin substrates.…”