Continuous flow enantioselective arylation of aldehydes with ArZnEt using triarylboroxins as the ultimate source of aryl groups

• Julien Rolland,
• Xacobe C. Cambeiro,
• Carles Rodríguez-Escrich and
• Miquel A. Pericàs

Beilstein J. Org. Chem. 2009, 5, No. 56, doi:10.3762/bjoc.5.56

• obtained in slightly lower yield and enantioselectivity (entry 1, Table 1). This is probably due to the fact that the triethylboroxin co-product can trigger a non-enantioselective pathway for the arylation reaction; in fact, a decrease in the amount of (PhBO)3, as well as an increase in the amount of ZnEt2

• difficulty comes from the Bolm laboratory and has been based on the use of the comparatively less reactive mixed species PhEtZn, easily prepared from a mixture of Ph2Zn and Et2Zn [10][11][12][13]. With this strategy, it has become possible to achieve good levels of enantioselectivity in the arylation

• reaction, although usually at the cost of low catalytic activity, high catalytic loadings being required for the achievement of satisfactory yields [14][15]. In contrast, β-amino alcohol 1 (Figure 2), developed in our laboratory [16], showed high activity and enantioselectivity in the ethylation [16

Regioselective alkynylation followed by Suzuki coupling of 2,4-dichloroquinoline: Synthesis of 2-alkynyl- 4-arylquinolines

• Ellanki A. Reddy,
• Aminul Islam,
• K. Mukkanti,
• Venkanna Bandameedi,
• Dipal R. Bhowmik and
• Manojit Pal

Beilstein J. Org. Chem. 2009, 5, No. 32, doi:10.3762/bjoc.5.32

• derivatives earlier [7][8][9][10][11][12][13][14][15][16][17]. Next, in order to prepare 2-alkynyl-4-arylquinolines (5) we planned to exploit the reactivity of chloro group of 3 towards Suzuki arylation reaction. Accordingly, a variety of arylboronic acids were coupled with 3 and results of this study are

N-Arylation of amines, amides, imides and sulfonamides with arylboroxines catalyzed by simple copper salt/EtOH system

• Zhang-Guo Zheng,
• Jun Wen,
• Na Wang,
• Bo Wu and
• Xiao-Qi Yu

Beilstein J. Org. Chem. 2008, 4, No. 40, doi:10.3762/bjoc.4.40

• copper-mediated N-arylation reaction plays an important role in organic synthesis since the resultant products, arylamines and N-arylheterocyclic compounds, are ubiquitous compounds in pharmaceuticals, crop-protection chemicals and material science [1][2][3][4]. In 1997, the copper-mediated heteroatom

• arylation reaction using arylboronic acids as aryl donors was discovered by Chan, Evans and Lam independently [5][6][7]. Based on these studies, further improvements to the catalytic variation of organoboron compounds cross coupling have been reported. Among these organoboron compounds, arylboronic acids

• anhydride form (boroxine) and not the free acid [21]. This result prompted us to study arylboroxines as aryl donors instead of arylboronic acids in the cross-coupling reaction, since arylboroxine is more active and may remarkably accelerate the reaction. In this paper we found that N-arylation reaction can

Synthesis of dihydrophenanthridines by a sequence of Ugi-4CR and palladium- catalyzed intramolecular C-H functionalization

• Florence Bonnaterre,
• Michèle Bois-Choussy and
• Jieping Zhu

Beilstein J. Org. Chem. 2008, 4, No. 10, doi:10.3762/bjoc.4.10

• developed an efficient palladium-catalyzed intramolecular CH-arylation reaction leading, under ligandless conditions, to dihydrophenanthridines in good to excellent yields. In combination with the Ugi four-component reaction, this medicinally important heterocycle can be easily prepared in two steps from