The vilsmeier‐haack formylation of 1,2,3‐trimethylindole

Bastianelli, Carlo; Cipiciani, Antonio; Clementi, Sérgio; Giulietti, Gianfranco

doi:10.1002/jhet.5570180645

Cited by 14 publications

(1 citation statement)

References 16 publications

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“…Product 2 was then converted to 3 using the Vilsmeier-Haack formylation reaction (42% yield). 7 Diethyl isopropylidenesuccinate (6) was prepared by Stobbe condensation (86% yield). 8 Stobbe condensation of indole-2-carbaldehyde (3) with diethyl isopropylidenesuccinate (6) followed by hydrolysis and intramolecular acid anhydride formation yields 2-indolylfulgide (E-7 and Z-7) with 23% yield from 3 to 7, where E-7 was separated as the main product.…”

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Photochromic cross-linked copolymer containing thermally stable fluorescing 2-indolylfulgimide

2000

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Photochromic cross-linked copolymer containing thermally stable fluorescing 2-indolylfulgimide

2000

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The Vilsmeier Reaction of Non‐Aromatic Compounds

Jones

Stanforth

2000

Organic Reactions

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This chapter extends the discussion to reactions between the Vilsmeier‐Haack reagent (subsequently referred to as the Vilsmeier reagent for brevity) and any other compounds in which a carbon‐carbon bond is formed. The discussion thus excludes reactions in which the Vilsmeier reagent acts as a chlorinating agent (for example in the preparation of acid chlorides), or in which it forms carbon‐oxygen or carbon‐nitrogen bonds, unless these are accompanied by formation of a carbon‐carbon bond. For a discussion of the nature of the reagent and of the mechanism of the reaction, the earlier chapter in vol. 49 should be consulted. There are also a number of reviews that deal at length with mechanisms of reactions involving the Vilsmeier reagent, notably those by Jutz and Marson, and hence this chapter will concentrate on applications, with brief mention of mechanisms when necessary. Wizinger has pointed out that alkenes could react with the Vilsmeier reagent, but his only examples were styrenes where the intermediate carbocation has considerable stability. Hydrolysis gives the cinnamaldehyde. In principle, any alkene which is not too sterically hindered can undergo this reaction, but the Vilsmeier reagent has low reactivity as an electrophile, and in practice activation is often necessary. The addition depends on the HOMO of the alkene, and anything increasing the HOMO energy will aid reaction, as for example further conjugation (dienes, trienes, etc.) or the presence of an electron‐donating substituent. Hence aldehydes and ketones are active in their enol forms, and enol ethers and enamines are good substrates. Indeed, all additions covered by this chapter can be regarded as alkene additions, even those on active methyl groups attached to electron‐deficient rings. As with any reaction involving carbocation intermediates, rearrangements are possible; the initial products are sometimes enamines, and this can give rise to polysubstitution. The substrates are grouped into eleven major subsections; references to reviews of particular relevance will be found in the appropriate subsection.

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Vilsmeier Formylation

2010

Comprehensive Organic Name Reactions and Reagents

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This reaction is a formylation of an electron‐enriched aromatic or heterocyclic compound using N , N‐ disubstituted formamide (e.g., DMF) as the acylating agent in the presence of an activating reagent, such as POCl 3 and is generally known as the Vilsmeier formylation. The study finds that this reaction is applicable only for aromatics that are more reactive than benzene. In addition, the Vilsmeier formylation has a similar trend of regioselectivity as observed in the Friedel‐Crafts acylation, which primarily depends on the electron density of the attacked site on the substrate. Furthermore, the benzene ring can be easily formylated when the ring is activated by complexing with Mn(CO) 3 and many acyl chlorides have been suggested as effective activating reagents. Overall, this reaction is a very useful formylation method and has wide applications in the organic synthesis.

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The vilsmeier‐haack formylation of 1,2,3‐trimethylindole

Abstract: The title reaction vields mainlv a side-chain monosubstituted formyl derivative, namely 2-(1,3-dimethyl. indo1yl)acetaldehyde.

Cited by 14 publications

References 16 publications

Photochromic cross-linked copolymer containing thermally stable fluorescing 2-indolylfulgimide

Photochromic cross-linked copolymer containing thermally stable fluorescing 2-indolylfulgimide

The Vilsmeier Reaction of Non‐Aromatic Compounds

Vilsmeier Formylation

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