BF₃−H₂O Catalyzed Hydroxyalkylation of Aromatics with Aromatic Aldehydes and Dicarboxaldehydes: Efficient Synthesis of Triarylmethanes, Diarylmethylbenzaldehydes, and Anthracene Derivatives

Abstract

BF(3)-monohydrate is found to be an efficient and strong acid catalyst as well as an effective protosolvating medium suitable for the hydroxyalkylation of arenes with aromatic aldehydes. This reaction has been extended to aromatic dialdehydes, such as terephthalic dicarboxaldehyde and isoterephthalic dicarboxaldehyde, for the efficient synthesis of diarylmethylbenzaldehydes, which are useful synthons for various organic transformations. Further, successful one step convergent synthesis of various synthetically useful anthracene derivatives from phthalaldehyde was also achieved. BF(3)-H(2)O is less expensive and acts as an efficient substitute for nonoxidizing strong protic acids/superacids.

Microwave-Assisted Nafion-H Catalyzed Friedel–Crafts Type Reaction of Aromatic Aldehydes with Arenes: Synthesis of Triarylmethanes

“…In stronger acid, CF 3 was instantaneous with 83% yield of the isolated product. Similar studies are reported in liquid Brønsted superacids using isomeric pyridine and quinoline carboxaldehydes as well as aromatic dialdehydes [21,22]. This study suggests that the monoprotonated aromatic aldehydes are not strong enough to react with aromatics.…”

“…The products are all well known [and were identified on the basis of their 1 H and 13 C NMR (Varian 400 MHz) and mass spectra (Thermo Finigan GC coupled with a mass spectrometer) as well as with comparison with the literature data [22]. The isomer distribution of the product was determined by 1 …”

A new practical synthesis of triaryl and trisindolylmethanes under solvent-free reaction conditions

“…; in a pressure tube and under closed conditions). 15 This stable complex has been used in a dual role, as a suitable protic solvent/protosolvating medium and as a strong Brønsted acid catalyst.…”

Synthesis of natural ether lipids and 1-O-hexadecylglycero-arylboronates via an epoxide-ring opening approach: Potential antifouling additives to marine paint coatings

“…The unsuccessful attempt to yield the 1-Ohexadecylglycero-furylboronate (7g) is probably related to the opening of the furan ring system by BF3-monohydrated (H2O + --BF3) which is an efficient and strong acid catalyst formed during the reactional process [23]. In addition to that, the reaction also did not work well to obtain (7h) due the reactivity of BF3.O (C2H5)2 which interacts preferably with the nitrogen atom of the pyridinyl ring instead of promoting the desired pathway of chemical transformation (Table 1).…”