Orthoamide, LVII [1]. Lassen sich aromatische Aldehyde nach Fries aus Arylformiaten hersteilen? / Orthoamides, LVII [1]. Can Aromatic Aldehydes be Prepared from Aryl Formates via the Fries Rearrangement?

Abstract

The aromatic hydroxyaldehydes 3a-3g, 5a-5f, 8 , 10 can be prepared by the action of BCl3, BBr3 or trifluoromethanesulfonic acid, on the aryl formates 1a-1f, 4a-e, 7, 9 via Fries rearrangement. BBr3 is more effective than BCl3. The activating ability of BBr3 can be improved by addition of FeCl3. Rearrangements which are induced by trifluoromethanesulfonic acid can give rise to the formations of regioisomers, which might be different from the products formed when the reaction is performed with Lewis acids. The yields of the aldehydes are lowered by subsequent condensation reactions. This view was confirmed by the isolation of a condensation product, which was characterized as a dibenzo[a,j]xanthene derivative 6 by crystal structure analysis. For the Fries rearrangement of formyl groups a new mechanism is proposed. 2-Hydroxy-1-naphthaldehyde 5c can be obtained in good yield from formic acid, BBr3, and 2 -naphthol.

New Methods for the Preparation of Aromatic Aldehydes

“…Compounds of this type should be formed if mixtures of formic acid and hyroxyarenes are treated with boron halides. In accordance with this assumption, 2‐hydroxy‐1‐naphthaldehyde ( 24 ) was obtained in a yield of 70% from formic acid, 2‐naphthol, and boron tribromide in 1,2‐dichloroethane 42. The same aldehyde was obtained in about 47% yield if boron trichloride was used instead of boron tribromide 53…”

“…When 4‐ tert ‐butylphenyl formate ( 27 ) was irradiated for 39 h in benzene, 5‐ tert ‐butyl‐2‐hydroxybenzaldehyde ( 28 ) could be isolated in 7% yield 46. The photochemical procedure may have high synthetic potential, since it has been noted that 9‐phenanthrenyl formate ( 29 ) is rearranged to 10‐hydroxyphenanthrene‐9‐carbaldehyde ( 30 ) on standing in sunlight 42 …”

“…In the Fries reaction of aryl formates, intermediates such as 26 were considered 42. Compounds of this type should be formed if mixtures of formic acid and hyroxyarenes are treated with boron halides.…”

One-pot synthesis of ortho-hydroxycinnamate esters

“…(+)-Powelline 132 has been isolated from several Amaryllidaceae species like Crinum bulbispermum 44 and Crinum moorei. 45 Several members in this class of alkaloids display interesting biological properties such as acetylcholinesterase inhibition, 46 cytotoxicity, 47 and antimalarial 48 effects. Due to their interesting structures, limited supply, and their bioactivities, these natural products constitute obvious targets for total synthesis.…”

Zur Formylierung von Hydroxy- und Alkoxyaromaten mit Ameisensäure

“…Vor geraumer Zeit berichteten wir über die Darstellung von aromatischen Aldehyden aus Arylformiaten (Fries-Verschiebung) [18,19]. Durch einen ersten orientierenden Versuch -die Reaktion von 2-Naphthol mit Ameisensäure in Gegenwart von Bortribromid zu 2-Hydroxynaphthaldehyd (Schema 4) -konnte der seinerzeit für die Fries-Verschiebung vorgeschlagene Mechanismus untermauert werden.…”