Organocatalytic Tail-to-Tail Dimerization of Olefin: Umpolung of Methyl Methacrylate Mediated by N-Heterocyclic Carbene

Abstract

Highly selective tail-to-tail dimerization of methyl methacrylate has been realized by an N-heterocyclic carbene catalyst, giving dimethyl 2,5-dimethyl-2-hexenedioate with an E/Z ratio of 95:5 in 86% isolated yield. The umpolung mechanism is proposed on the basis of interception of the intermediates using ESI-MS analyses and deuterium-labeling experiments.

N‐Heterocyclic Carbene Catalyzed Umpolung of Michael Acceptors for Intermolecular Reactions

“…(2); EWG = electron-withdrawing group], [5] the analogous transformation for the b functionalization of Michael acceptors is less developed, [6] and an organocatalytic approach that utilizes an umpolung strategy remains to be explored. [7] Herein, we report the NHC-catalyzed umpolung of Michael acceptors, followed by an intermolecular addition to activated olefins that leads to the b-selective formation of linear dimers, which are potential precursors for the synthesis of fine chemicals and polymer intermediates [Eq. (3)].…”

Synthesis and properties of heteroaromatic carbenes of the imidazole and triazole series and their fused analogues

“…Thus, carbene initiated growth of the alkane chain is possible in the reaction products. This was confirmed by Matsuoka et al, 348,349 who studied a reaction which underwent an unusual catalytic dimerization (tail-to-tail) upon heating methyl methacrylate 87A (Scheme 87). Related olefins were also activated by electron withdrawing groups in the presence of carbenes, e.g., 86A (10 mol%).…”

Theoretical study of the mechanism of the N-heterocyclic carbene-catalyzed cyclotetramerization of acrylates

“…The next step can either involve the zwitterionic intermediate with a proton transfer [17][18][19][20] or a further addition to electrophilic centers [21][22][23]. In 2013, Matsuoka et al [24] studied the NHC-catalyzed cyclotetramerization of acrylates leading to trisubstituted cyclopentenones under mild conditions (Fig.…”