The first DMAP-mediated palladium-free Tsuji–Trost-type reaction of cyclic and acyclic Baylis–Hillman alcohols with active methylene compounds

RegioselectiveS-allylation of thiols with cyclic Baylis–Hillman acetates

“…According to our previous work [28,29] and previous papers [31,32,[34][35][36] on the allylic nucleophilic substitutions of cyclic BH adducts, we believe that the reaction starts with a β-conjugate addition of sodium thiolate to Michael acceptor 1a, followed by the elimination of acetate ion, to afford the intermediate I. Subsequent β -conjugate addition of sodium thiolate to I and elimination of the thiolate ion, provides the thermodynamically stable product 2a, which is then the result of two consecutive S N 2 reactions through a one pot addition-elimination sequence.…”

“…In the course of our study on the chemistry of cyclic BH adducts, we have previously reported the S-allylation of alkyl alcohols and thiols with 2-(hydroxymethyl)cyclohex-2-en-1-one in the presence of p-TsOH [27] as well as the C-allylation of β-dicarbonyl compounds with either cyclic BH acetates [28] or even with their corresponding alcohols, [29] through a Tsuji-Trost-type reaction. To the best of our knowledge, the S-allylation of thiols with cyclic BH acetates has not been extensively studied in the presence of a transition metal-catalyst or under catalyst-free conditions.…”

Allylation of active methylene compounds with cyclic Baylis–Hillman alcohols: a DFT study

“…The chosen compounds are those used in the experiment carried out by Mhasni and Rezgui [15] and are given in Table 1. All the stationary points on the potential energy surface (reactants, transition structure, intermediates and products) have been optimized and fully characterized by a frequency calculation.…”

The first Et3N-mediated transesterification of β-keto esters using Baylis–Hillman alcohols

“…A reaction mechanism of the latter reaction, based on the strong nucleophilic character of DMAP, was previously proposed. 14 In contrast, Et 3 N is usually used as a nitrogen Brønsted base, stronger than both DMAP and 2,6-lutidine. 24 The latter is weakly nucleophilic and is usually used in organic synthesis as a hindered mild base, weaker than Et 3 N. 25 The high selectivity of the reaction of 1a with ethyl acetoacetate in favour of 3a, suggested that both Et 3 N and 2,6-lutidine remarkably acted in this protocol as Brønsted bases.…”

“…14 With the exception of the DMAP-catalysed ester exchange reactions, 4 it is notable that none of the above methods reported that tertiary bases, such as Et 3 N could catalyse transesterification of bketo esters. In continuation of our previous study on the chemistry of BH adducts towards b-dicarbonyl compounds, 14e16 we report herein a simple and efficient procedure for the transesterification of b-keto esters with various alcohols 1aec and 4aec, 13,17 using commercially available and inexpensive triethylamine, for the first time, as a Brønsted base catalyst.…”