H-type Zeolite-Catalyzed 1,4-Addition of Benzene Derivatives to Labile Acrolein

Abstract

The 1,4-addition of benzene derivatives to acrolein is a straightforward way to synthesize 3-arylpropanals. A survey of acid catalysts for the 1,4-addition of methoxy-substituted benzenes to acrolein revealed that H-Beta and H-Y were the most suitable catalysts. We hypothesized three side-reactions: (1) the double 1,4-addition of acrolein to the starting benzene derivatives, (2) the FriedelCrafts-type alkylation to the desired product, and (3) the self-polymerization of acrolein. The type (3) side-reaction was inhibited by two different methods which kept the concentration of acrolein low in the reaction mixture or in the zeolite pores. First, acrolein monomers were in situ generated through the gradual monomerization of an acrolein cyclic trimer. Second, using a reaction solvent lowered the acrolein concentration in the zeolite pores due to the competitive adsorption. We discovered that the content of monomeric acrolein in a solvent was closely related to the polarity of the solvent. Actually, both methods improved the yields for the 1,4-additions of 1,3-dimethoxybenzene to acrolein. Other electronrich benzene derivatives, such as phenol and N,N-dimethylaniline, were also applicable to the 1,4-addition reactions.

A Green Step to New Monomers and Their Polymerization

“…Purification of the dark red 4‐(4‐hydroxyphenyl)butan‐2‐one raw product by column chromatography followed by recrystallization led to colorless crystalline 4‐(4‐hydroxyphenyl)butane‐2‐one (Figure S4 (NMR spectra), Figure S5 (FT IR spectrum), Figure S6 (Crystals)). This compound is also known from the literature as both natural material and synthetic staff . Furthermore, 4‐(4‐hydroxyphenyl)butane‐2‐one was additionally synthesized in a twostep synthetic pathway described in the supporting information (Scheme S1).…”

Spirofused and Annulated 1,2,4‐Trioxepane‐, 1,2,4‐Trioxocane‐, and 1,2,4‐Trioxonane‐Cyclohexadienones: Cyclic Peroxides with Unusual Ring Conformation Dynamics

“…In addition to spirofused cyclic peroxides, this approach also allows the synthesis of annulated peroxides; for example, the 3‐hydroxymethylated phenol 17 was successfully converted into the seven‐membered cyclic peroxide 19 via the corresponding hydroperoxide 18 (Scheme ) in 41 % overall yield (Figure ).…”

Advances in the synthesis and applications of raspberry ketone: A review

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