Iron‐Catalysed Markovnikov Hydrothiolation of Styrenes

Abstract

The bis(triflimide)ironA C H T U N G T R E N N U N G (III) salt catalyzes the hydrothiolation of styrenes in a Markovnikov fashion with good selectivities and high yields. After isolation, different benzylic thioethers are obtained. This ironA C H T U N G T R E N N U N G (III) catalyst is unique in terms of regioselectivity and represents a sustainable and economic alternative to those processes based on stoichiometric reagents. Scheme 1. Possible reaction pathways for the hydrothiolation of double bounds.

Iron Catalysis in Organic Synthesis

“…855 The reaction proceeded in Markovnikov selectivity affording the corresponding benzylic thioethers in high yields.…”

Iron(III) Triflimide as a Catalytic Substitute for Gold(I) in Hydroaddition Reactions to Unsaturated Carbon–Carbon Bonds

“…Stability of triflimide salts: The traditional division into Brønsted and Lewis catalysis is difficult to be separated when in situ generated protons can contribute to the catalytic activity of some metals. [31,32] Triflimide metal salts [M n + A C H T U N G T R E N N U N G (NTf 2 ) n ], particularly those with gold, have gained much attention in the last years [15,16,21,[33][34][35][36] due to their high Lewis acidity and easy handling relative to the corresponding triflimidic acid (HNTf 2 ). Despite the fact that these salts are readily hydrolizable, the possible role of acid protons on the final catalytic activity is not always tested.…”

“…[1][2][3][4][5][6][7][8][9][10][11][12][13] Nonetheless, there is much incentive to substitute expensive and toxic heavy late transition metals by cheaper, widely available, and environmentally-friendly first-row transition metals, such as iron. [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28] The aim of our work here is to study iron, gold, and triflimidic acid, representative examples of first-row and heavy late transition metals and Brønsted acids, respectively, as catalysts for hydroaddition reactions to p-carbophilic unsaturated CÀC bonds (alkenes and alkynes) of carbon, oxygen, nitrogen, and sulfur nucleophiles, a set of complete atom-economical reactions with growing potential in organic synthesis. [3,8,29,30] The study includes reactivity tests, isotopic labeling, in situ NMR and EPR experiments, and cyclic voltammetry, which have helped to shed light on the exact nature of the catalytic process and active sites involved.…”

Iron‐Catalysed Hydrofunctionalisation of Alkenes and Alkynes

“…[38] The opposite regioselectivity of addition occurred in the absence of a catalyst, and linear, antiMarkovnikov products 53 were formed through a radical reaction (Scheme 15 A). [39] "Hidden Brønsted acid" catalysis was discounted, as both triflic and triflimidic acid gave only low yields of Markovnikov product 52, along with high yields of anti-Markovnikov product 53 arising from the uncatalysed radical addition.…”