Formamide Catalysis Facilitates the Transformation of Aldehydes into Geminal Dichlorides

Abstract

Herein, a novel method for the transformation of aldehydes into geminal dichlorides based on phthaloyl chloride as reagent and N-formylpyrrolidine as Lewis base catalyst is disclosed. Given the mild reaction conditions, the current protocol is distinguished by high levels of functional group compatibility and scalability and is operationally simple. The in situ formation of a Vilsmeier Haack reagent type intermediate is likely to be essential for this organocatalytic nucleophilic substitution reaction.

A method of mild deoxydichlorination of aldehydes catalyzed by Triphenylphosphine oxide

“…1 H NMR (CDCl3, 400 MHz) δ (ppm): 6.33 (d, J = 7.6 Hz, 1H, CH), 6.40 (dd, J = 14.7 and 7.6 Hz, 1H, CH), 6.72 (d, J = 14.7 Hz, 1H, CH), 7.30-7.50 (m, 5H, HAr). 13 C NMR (CDCl3, 100 MHz) δ (ppm): 73.5, 127.1, 128.1, 129.0, 129.2, 132.5, 134.7 [53].…”

“…The proposed method works well with different unsaturated compounds, but gives a lower yield of 32% with aliphatic compounds. The proposed method exhibits the same catalytic activity as triphenylphosphine oxide [53]. Later Dr. Shipilovskikh with colleges proposed an alternative method for deoxydichlorination of aldehydes catalyzed by diphenyl sulfoxide, using a catalytic system of diphenyl sulfoxide (10 mol.%) and oxalyl chloride (1.5 equiv).…”

Deoxydichlorination of aldehydes catalyzed by Diphenyl sulfoxide

“…The identity of the products prepared by different methods was checked by comparison of their NMR spectra. 1 H and 13 C NMR spectra were recorded at 400 MHz for 1 H and 100 MHz for 13 C NMR at room temperature; the chemical shifts (δ) were measured in ppm with respect to the solvent (CDCl3, 1 Н: δ = 7.26 ppm, 13 C: δ = 77.16 ppm; [D6] DMSO, 1 Н: δ = 2.50 ppm, 13 C: δ = 39.52 ppm). Coupling constants (J) are given in Hertz.…”

“…However, research in this area is at an early stage in the study of such catalytic reaction. Although by now several effective protocols for the preparation of dichlorides from aldehydes catalyzed by a Lewis base have been disclosed [13,14], all possibilities for studying these reactions have not yet been realized (Scheme 1).…”

Deoxygenative Functionalizations of Aldehydes, Ketones and Carboxylic Acids

“…[23] Although hazardous reagents (e.g., CX 4 )u nder traditional Appelsc onditions were bypassed, ah alogen source such as 1,2-dihalogenated ethane (solvent) was needed in great excess in this case.F or this reason, Huy developed an improved protocol, in which aVilsmeier-Haack reagent was generated in situ from an amide catalyst and phthaloyl chloride to enable the deoxygenative dichlorination. [24] Bimetallic reagents are versatile intermediates in the synthetic community.A mong them, gem-diboronate holds aunique place owing to its potential for selective mono-and difunctionalizations on the same carbon based on the rich boron chemistry.I n2 017, Liusg roup delineated an elegant strategy to realize the deoxygenative gem-diborylation of aldehydes and ketones (Scheme 5D). [25,26] In their tentative mechanism, carbonyl vicinal diboration firstly takes place, generating the a-oxyboronates in the presence of ac opper catalyst.…”