Réaction régiospécifique des carbanions stabilisés avec la 2-(acétoxyméthyl)cyclohex-2-én-1-one: Synthèse de diénones bicycliques

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.…”

Efficient α-chlorination of 2-[(1-oxocyclohex-2-en-2-yl)methyl]-1,3-dicarbonyl Compounds Using Sodium Hypochlorite

“…In connection with our studies on the behaviour of Baylis-Hillman adducts towards various nucleophiles, 28,29 we have reported a direct allylic substitution of alcohol 1 30 with β-keto esters and β-diketones, affording β-dicarbonyl derivatives 2 (Scheme 1). 27 Starting from β-dicarbonyl derivatives 2 in basic conditions, we have also described two synthetic routes to a new series of bicyclic dienones.…”

“…27 Starting from β-dicarbonyl derivatives 2 in basic conditions, we have also described two synthetic routes to a new series of bicyclic dienones. 28,31 We have also reported the PTSApromoted Robinson annelation of compounds 2, afforded, in a one-pot process, a variety of hydroxytetrahydronaphthyl carbonyl compounds. 32 In connection with our study on the reactivity of the multifunctional derivatives 2, we now report that the use of sodium hypochlorite in the presence of K 2 CO 3 in a commonly available solvent such as THF, is an efficient medium for regioselective monochlorination of a new series of 1,3-dicarbonyl derivatives 2.…”

Et3B-mediated and palladium-catalyzed direct allylation of β-dicarbonyl compounds with Morita–Baylis–Hillman alcohols

“…As part of an ongoing program studying the behavior of MBH derivatives [33] towards β-dicarbonyl compounds, our research group [34–37] has reported an interesting synthesis of bicyclic dienones in a one-pot process involving the reaction of 2-(acetoxymethyl)cyclohex-2-enone with 1,3-dicarbonyl compounds using K 2 CO 3 as a weak base.…”