Iodine Promoted Conversion of Esters to Nitriles and Ketones under Metal-Free Conditions

Abstract

We report a novel strategy to prepare valuable nitriles and ketones through the conversion of esters under metal-free conditions. By using the I2/PCl3 system, various substrates including aliphatic and aromatic esters could react with acetonitrile and arenes to afford the desired products in good to excellent yields. This method is compatible with a number of functional groups and provides a simple and practical approach for the synthesis of nitrile compounds and aryl ketones.

Iron‐Catalyzed Deoxynitrogenation of Carboxylic Acids with Cyanamides to Access Nitriles

“…The commercially available TsCN was also examined but led to a low yield of 3 a (entry 16). Notably, when acetonitrile is used as the nitrogenating reagent and solvent, the reaction cannot proceed, which is different from the documented work (entry 17) [14l,m] . At last, the inert atmosphere was proven to have little impact on the reaction (entry 18).…”

“…The other state‐of‐the‐art strategy is constructing a cyano group from the carboxylic acid functionality with a nitrogen atom donor (Scheme 1, B, right) [14] . However, because the carboxyl group is often thermodynamically and kinetically inert, this transformation usually requires harsh reaction conditions or large amounts of hazardous dehydrating reagents to drive the reaction equilibrium and reduce the amide byproduct [14a–p] . As a result, the practicability of these methods is quite limited.…”

A Reductive Benzylation for Benzenes Using Aroyl Chlorides and Triethylsilane Catalyzed by Aluminosilicate-Stabilized Silyl Cations on Montmorillonite

“…From 3,5-dibromobenzoyl chloride 1i, the desired product 3ia was obtained in a moderate yield together with the methylated by-product (entry 9). Concerning the heteroatom-containing aromatic carboxylic acid chlorides 1j, 1k and 1l, no corresponding coupling products were produced even after 24 h, and most of the acid chlorides were recovered together with trace amounts of the corresponding triethylsilyl ethers (entries [10][11][12]. These results imply that the reduction of the intermediate D (see below in Figure 4) with Et3SiH to a methyl group would prevail over the desired benzylation of benzene.…”

“…1,136.9,136.0,133.1,131.4,129.6,129.0,119.4,34.1,20.9,20.1. HRMS (EI) m/z (M + ) calcd for C16H17Br + : 288.0514, 290.0493, found 288.0516, 290.0504 4-Bromophenyl-2,4,6-trimethylphenylmethanone (4ad) 11) yellow oil 1 H NMR (400 MHz, CDCl3) δ 7.66 (d, 2H), 7.59 (d, 2H), 6.90 (s, 2H), 2.33 (s, 3H), 2.07 (s, 6H). 13 C NMR ( 101MHz, CDCl3) δ 199.…”

“…Figure 2 summarizes the precedent of the acid-catalyzed reductive Friedel-Crafts alkylation of arenes from carbonyl compounds and organosilanes: i) InBr3-catalyzed reduction of aromatic carboxylic acids; 9 ii) InI3-catalyzed reduction of aliphatic carboxylic acids or acid chlorides; 10 iii) TMSOTf, Cu(OTf)2, InCl3 or B(C6F5)3-catalyzed reduction of aldehydes or ketones; 10,11 and iv) CF3CO2H or B(C6F5)3-catalyzed reduction of aldehydes. 12 We now report the novel reductive benzylation of arenes using benzoic acid chlorides and Et3SiH catalyzed by the Lewis acidic Et3Si + -Mont − .…”