Suzuki–Miyaura Coupling Reaction of Boronic Acids and Ethyl Glyoxylate: Synthetic Access to Mandelate Derivatives

Abstract

The palladium-catalyzed coupling reaction of arylboronic acids with ethyl glyoxylate provides a straightforward method for the synthesis of mandelic esters. Pd 2 (dba) 3 ·CHCl 3 in combination with 2-di-tert-butylphosphanylbiphenyl as the catalytic system and Cs 2 CO 3 as the base were used. The reaction tolerates a wide range of functionalized boronic

Identification of a New Zinc Binding Chemotype by Fragment Screening

“…Palladiumcatalyzed Suzuki−Miyaura coupling reaction of the phenyl boronic acids 1a,b with ethyl glyoxylate generated the precursor mandelic acid ethyl esters 2a,b in good yield. 69 Condensation of 2a,b with urea or thiourea in the presence of NaOEt (21 wt % in ethanol), followed by acidification with HCl (1.0 N), provided the target compounds. 70 Compounds 18 and 19 were synthesized by acid mediated coupling of hydantoin with benzaldehydes 3a,b followed by hydrolysis, Scheme 2.…”

Asymmetric catalytic arylation of ethyl glyoxylate using organoboron reagents and Rh(i)–phosphane and phosphane–phosphite catalysts

“…11a,b With regard to the synthesis of mandelate derivatives, Francesco and coworkers reported a non-asymmetric Suzuki-Miyaura coupling reaction of organoboronic acids and ethyl glyoxylate using Pd(0) catalysts. 12 In 2012, Yamamoto and co-workers reported the addition of arylboronic acids to ethyl glyoxylate catalysed by a Ru/Me-BIPAM complex, giving mandelate derivatives in high yields and enantioselectivities.…”

“…11a,b With regard to the synthesis of mandelate derivatives, Francesco and coworkers reported a non-asymmetric Suzuki-Miyaura coupling reaction of organoboronic acids and ethyl glyoxylate using Pd(0) catalysts. 12 In 2012, Yamamoto and co-workers reported the addition of arylboronic acids to ethyl glyoxylate catalysed by a Ru/Me-BIPAM complex, giving mandelate derivatives in high yields and enantioselectivities. 13 Based on our previous work on the synthesis of ethyl mandelate derivatives using Rh(I)-NHC catalysts, 1d,e and our unsuccessful attempts at obtaining high enantioselectivities, we initiated a focused program at screening various chiral phosphorous ligands in an attempt at increasing the enantioselectivities.…”

Celebrating 20 Years of SYNLETT - Special Account On Palladium(II)-Catalyzed Additions of Arylboronic Acids to Electron-Deficient Alkenes, Aldehydes, Imines, and Nitriles

“…Insertion of the C-O double bond into a late transition metal-carbon bond is rare compared to that of C-C double bonds, but it was well established by Hartwig in a stoichiometric insertion of aldehydes into arylrhodium(I) complexes. 65 Palladium(II) complexes of tris(1-naphth- yl)phosphine (63, entry 1 of the table in Scheme 13), 37 JohnPhos (64, entry 2), 42 tol-binap (entry 3), 35 N-heterocyclic carbene 65 (NHC, entry 3), 40,41 and phosphiniteand phosphite-based palladacycles 26 and 27 (entries 5-7), 28,29,32 as well as a cationic bipyridyl complex 66 (entry 8) 38 catalyze arylation of aldehydes in the presence of a base (Scheme 13). It is remarkable that palladacycle 27a catalyzes the addition at room temperature for both aromatic and aliphatic aldehydes.…”

“…12 Although these precedents suffered from competitive Heck coupling and low catalyst efficiency, we found that dicationic [Pd(dppe)(PhCN) 2 ]X 2 (X = BF 4 , SbF 6 ) is a selective catalyst for 1,4-additions of ArB(OH) 2 , [13][14][15][16][17][18][19][20] ArBF 3 K, 21 ArSi(OR) 3 , 22 ArSiF 3 , and Ar 4 Bi 23 to unsaturated carbonyl compounds in an aqueous medium. This review focuses on such 1,4-additions of arylboronic acid [ArB(OH) 2 ] to electron-deficient alkenes and their enantioselective versions, and related chemistry reported in Grignard-type additions of arylboronic acid to aldehydes, 28,29,32,[34][35][36][37][38][39][40][41][42][43] imines, 29,44 and nitriles. 45,46 2…”