Regioselective nucleophilic addition of methoxybenzene derivatives to the beta-carbon of p-benzoquinone mono O,S-acetal

Nucleophilic functionalizations of indole derivatives using the aromatic Pummerer reaction

Because of the electron-rich property of indoles, direct functionalization strategies towards indoles generally involve electrophilic substitutions. In this paper, an efficient protocol for nucleophilic hydroxylation, halogenation and esterification of indoles via the aromatic Pummerer process was developed. With the advantages of readily accessible starting materials, simple operation and mild conditions, this protocol should be of interest to synthetic scientists.

Aromatic Pummerer reaction for the remote para- or ortho-benzyl nucleophilic functionalization

The classic Pummerer reaction involves an α-substituted sulfide via an elimination/addition of a thionium ion. In this paper, we reported a remote para- or ortho-benzyl nucleophilic functionalization using an aromatic Pummerer process. A plausible mechanism involving a quinone thionium intermediate was proposed to explain this reaction.

1-alkoxyvinyl esters: renaissance of half-century-old acyl donors with potential applicability

Among the various kinds of acyl donors, the 1-alkoxyvinyl esters have characteristic features, such as a high reactivity under nearly neutral conditions and the generation of neutral and volatile esters as single coproducts. Although their use in organic syntheses began in the middle of the 1950s, no significant progress has been seen. This is probably because the existing method of preparing alkoxyvinyl esters used toxic mercuric salts and was not totally applicable for those esters having functionalized acyl moieties. We have discovered that the use of a catalytic amount of the less toxic [RuCl2(p-cymene)]2 effectively accelerates the addition of carboxylic acids to ethoxyacetylene to give ethoxyvinyl esters bearing a variety of functionalized acyl groups in high yields. This discovery has opened a new avenue for developing new reactions and new synthetic methodologies based on the design and use of these acyl donors with suitable functional groups. Such examples include (i) the installation of hydrophilic acyl moieties on biologically active compounds, (ii) asymmetric Pummerer-type reactions, (iii) aromatic Pummerer-type reactions, (iv) the lipase-catalyzed desymmetrization of symmetrical 1,3-diols, and (v) lipase-catalyzed domino reactions. Future possibilities for these acyl donors are also discussed.