Tandem Acyl Substitution/Michael Addition of Thioesters with Vinylmagnesium Bromide
A tandem reaction of thioesters with vinylmagnesium bromide is reported. The initial acyl substitution provides an α,β-unsaturated ketone which further reacts with the liberated thiolate. This transition-metal-free synthesis of β-sulfanyl ketones takes place under mild reaction conditions, whereas the addition of a second Grignard molecule is almost completely suppressed. The carefully chosen parameters enabled the transformation of different substrates in moderate to good yields.
Hirschbeck, Vera,B?ldl, Marlene,Gehrtz, Paul H.,Fleischer, Ivana
supporting information
p. 2578 - 2582
(2019/04/17)
Nickel-Catalyzed Coupling of Arylzinc Halides with Thioesters
The Pd-catalyzed Fukuyama reaction of thioesters with organozinc reagents is a mild, functional-group-tolerant method for acylation chemistry. Its Ni-catalyzed variant might be a sustainable alternative to expensive catalytic Pd sources. We investigated the reaction of S-ethyl thioesters with aryl zinc halides with hetero- and homotopic Ni precatalysts and several ligands. The results show that both homo- and heterotopic species may contribute to catalysis. The substrate scope using an operationally homogeneous defined Ni complex was established. Acyl radicals are postulated as short-lived intermediates.
Gehrtz, Paul H.,Kathe, Prasad,Fleischer, Ivana
supporting information
p. 8774 - 8778
(2018/06/26)
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