O-Benzenedisulfonimide as a Reusable Brønsted Acid Catalyst for Hetero-Michael Reactions

Abstract

The hetero-Michael reactions between various oxygen, sulphur and nitrogen nucleophiles and α,β-unsaturated compounds were carried out in the presence of catalytic amounts of obenzenedisulfonimide as Brønsted acid organocatalyst. The reaction conditions were very mild and the yields of target products were good. The catalyst was easily recovered and purified, ready to be used in further reactions. This ability grants economic and ecological advantages.

Facile Sulfa-Michael Reactions with Sodium Arylsulfinates in Water: The Promotion of Water on the Reaction

“…According to the computing results, the protonation of chalcone 2a is the key step of the transformation. In addition, It is generally agreed the protonation is the first step of the polar reactions under acidic conditions, , so the first step of the sulfa-Michael reaction is the protonation of chalcone 2a as well as other Michael acceptors, such as acrylamides, acrylates and simple alkyl enones (Scheme ). Water could enhance the process via speeding the proton transfer and stabilizing the cationic intermediate 9 , presumably owing to its polarity effects. − The cationic intermediate 9 may be trapped by water, but very low concentration of 9 is required to initiate the reaction owing to its high reactivity, and 1a have better nucleophilicity than water .…”

Studying the Morita-Baylis-Hillman Reaction in Continuous Flow Using Packed Bed Reactors

“…13 In same instance following sideproduct was isolated: 4-Butoxybutan-2-one. 30 The title compound was purified using flash chromatography eluting with pentane/EtOAc (3:1) and was obtained as a colorless oil. 1 H NMR (400 MHz, CDCl 3 ): 3.67 (t, J = 6.3 Hz, 1H), 3.42 (t, J = 6.6 Hz, 1H), 2.67 (t, J = 6.3 Hz, 1H), 2.18 (s, 3H), 1.53 (pent, J = 8.0 Hz, 2H), 1.35 (sekt, J = 7.6 Hz, 1H), 0.91 (t, J = 7.4 Hz, 3H).…”

Aza‐Michael Reaction: A Decade Later – Is the Research Over?

“…Moreover, the catalyst can be easily recovered and reused in further reactions. [99] The aza-Michael addition of aromatic and aliphatic amines and sulfonamides to enones and acrylic acid derivatives (nitrile 1 and esters 2 b, c) has been carried out using the zeolite ZSM-5-SO 3 H as solid acid catalyst under solvent-free conditions. The target adducts 47 are obtained in good to excellent yields (Scheme 26).…”

“…Both aliphatic and aromatic primary amines readily react with acrylic acid derivatives (esters 2 b and nitrile 1 ) as well as 4‐hexen‐3‐one and nitrostyrene 9 (Ar=Ph) in the presence of this catalyst (5 mol %) to afford the Michael adducts in good yields. Moreover, the catalyst can be easily recovered and reused in further reactions [99] …”