A New Catalytic Activity of Antimony(III) Chloride in Palladium(0)-Catalyzed Conjugate Addition of Aromatics to .alpha.,.beta.-Unsaturated Ketones and Aldehydes with Sodium Tetraphenylborate and Arylboronic Acids

Abstract

A remarkable catalytic effect of antimony(III) chloride is disclosed in palladium(0)-catalyzed conjugate addition of aromatics to ,/3-unsaturated ketones and aldehydes with sodium tetraphenylborate and arylboronic acids in acetic acid at 25 °C. Several other metal chlorides such as AICI3, SnCl4, AsC13, TiCl4, FeCl3, M0CI5, and CeCl3 are also effective in some cases, but SbCl3 is the salt of choice. Two key steps are proposed for this reaction: one is the oxidative addition of a C-B bond to Pd(0) forming an arylpalladium species, and the other is the formation of an antimony enolate derived from the initial coordination of SbCl3 to the carbonyl oxygen of an organopalladium intermediate.

Rhodium‐ and Palladium‐Catalyzed Asymmetric Conjugate Additions

“…In 1995, Uemura and coworkers reported [1] that organoboronic could be used in the Pd-catalyzed addition onto enones. This reaction was performed under acidic 1) At its peak in 2008, the price of Rh (US$ 10 000 per ounce; US$ 300 per gram) was 23-fold higher than that of Pd (US$471 per ounce; US$15 per gram).…”

“…Since the seminal report by Uemura [1] in 1995 for palladium, and by Miyaura in 1997 for rhodium [2], the late transition metal-catalyzed conjugate addition of organoboron reagents to activated alkenes has emerged as one of the most functional group-tolerant and reliable carbon-carbon bond-forming processes. The maturity of this methodology is such that it has become an ideal testing ground for new ligand concepts and design, as will be illustrated throughout this chapter.…”

“…For more in-depth and comprehensive accounts, the reader should consult a number of excellent reviews that are available on this subject [6][7][8][9][10][11][12][13][14][15][16]. The first example of conjugate addition of an arylboronic acid to an enone catalyzed by transition metal complexes can be traced back to a report from 1995 by Uemura and coworkers [1]. This reaction was carried out ligand-less and with a high catalyst loading (10 mol%).…”

Addition reaction of arylboronic acids to aldehydes and α,β-unsaturated carbonyl compounds catalyzed by conventional palladium complexes in the presence of chloroform

“…The analytically pure ketone was obtained by chromatography on silica gel. When other enones and arylboronic acid were used, usually the reaction was carried out at 80°C for [24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40]methanol (3aa) [15] 1 H NMR (CDCl 3 ): d 2.63 (brs, 1H, ÀOH), 5.82 (s, 1H, ÀCHOH), 7.24-7.42 (m, 5H, -Ar), 7.49-7.58 (m, 4H, -Ar), 13 C NMR (CDCl 3 ) d 75. 9,111.3,119.1,126.9,127.2,128.5,129.1,132.5,143.0,methanol (3ab) [16] 1 H NMR (CDCl 3 ): d 2.42 (d, J = 2.7 Hz, 1H, ÀOH), 5.84 (d, J = 2.1 Hz, 1H, -CHOH), 7.…”

“…Methyl 3-phenylpentanoate (5am) [31] 1 H NMR (CDCl 3 , 300 MHz) d 0.78 (t, J = 7.2 Hz, 3H, -CH 3 ), 1.54-1.75 (m, 2H, ÀCH 2 CH 3 ), 2.52-2.67 (m, 2H, ÀCH 2 CO), 2.95-3.05 (m, 1H, ÀCHAr), 3.55 (s, 3H, -OCH 3 ), 7.13-7.29 (m, 5H, -Ar); 13 [32] 1 H NMR (CDCl 3 , 300 MHz) d 0.83 ((t, J = 7.2 Hz, 3H, -CH 3 ), 1.68-1.93 (m, 2H, -CH 2 CH 3 ), 2.57 (t, J = 7.2 Hz, 2H, -CH 2 CN), 2.78-2.85 (m, 1H, -CHAr), 7. 16-7.34 (m, 5H, -Ar); 13 C NMR (CDCl 3 , 75 MHz) d 12.2,25.1,28.3,44.2,118.9,127.4,127.5,129.0,cyclohexanone (5ba) [33] 1 H NMR (CDCl 3 , 300 MHz) d 1.69-1.86 (m, 2H), 2.01-2.15 (m, 2H), 2.29-2.58 (m, 4H), 2.89-2.98 (m, 1H, -CHAr), 3.76 (s, 3H, -OCH 3 ), 6.82-6.87 (m, 2H, -Ar), 7.09-7.14 (m, 2H, -Ar); 13 C NMR (CDCl 3 , 75 MHz) d 25.8,33.3,41.5,44.3,49.5,55.5,114.2,127.7,136.7,158.3,cyclohexanone (5da) [29] 1 H NMR (CDCl 3 , 300 MHz) d 1.69-1.82 (m, 2H), 2.00-2.13 (m, 2H), 2.30 (s, 3H, -CH 3 ), 2.32-2.56 (m, 4H), 2.89-2.96 (m, 1H, -CHAr), 7.06-7.12 (m, 4H, -Ar); 13 C NMR (CDCl 3 , 75 MHz) d 21.4,25.9,33.2,41.5,44.7,49.4,126.6,129.6,136.3,141.6,cyclohexanone (5ea) [34] 1 H NMR (CDCl 3 , 300 MHz) d 1.72-1.88 (m, 2H), 2.04-2.18 (m, 2H), 2.31-2.59 (m, 4H), 2.94-3.03 (m, 1H, -CHAr), 6.99 (m, 2H, -Ar), 7. 13-7.19 (m, 2H, -Ar); 13 C NMR (CDCl 3 , 75 MHz) d 25.7, 33.2, 41.4, 44.3, 49.4, 115.6 (d, J = 21.1 Hz, 2C, -C-CF), 128.2 (d, J = 8.0 Hz, 2C, -C-C-CF), 140.2, 161.6 (d, J = 262.6 Hz, 1C, -CF), 210.8; 19 F NMR (CDCl 3 , 282 MHz) d À116.5.…”