Details

Autor(en) / Beteiligte

• Schaarschmidt, Dieter
• Grumbt, Martin
• Hildebrandt, Alexander
• Lang, Heinrich

Titel

A Planar-Chiral Phosphino(alkenyl)ferrocene for Suzuki-Miyaura C-C Coupling Reactions

Ist Teil von

• European journal of organic chemistry, 2014-10, Vol.2014 (30), p.6676-6685

Ort / Verlag

Weinheim: WILEY-VCH Verlag

Erscheinungsjahr

2014

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Planar‐chiral phosphinoferrocene [Fe(η5‐C5H3‐1‐PPh2‐2‐(E)‐CH=CHPh)(η5‐C5H5)] (4) was applied in the presence of palladium in Suzuki–Miyaura couplings for the synthesis of sterically congested biaryls. The catalytic activity arises from homogeneous palladium phosphine complexes, of which the potential pre‐catalyst [Pd(4)2Cl2] was characterized structurally. The catalytic system is excellently suited for the synthesis of tri‐ortho‐substituted biaryls under mild conditions (0.1 mol‐%, 50–100 °C), whereas its application towards the synthesis of tetra‐ortho‐substituted biaryls is quite limited. Comparing the performance of the reaction with 4 as catalyst and a range of substrates with differing ortho substituents suggests that transmetalation is rate determining. Complex (Sp)‐4 was used in atropselective couplings, wherein enantioenrichments of up to 36 % were achieved. The stereoselectivity depends to some extent on the steric properties of the boronic acids; however, slight changes at the aryl halides influence the enantioselectivity. Planar‐chiral phosphino(alkenyl)ferrocene 4 was applied in the presence of [Pd2(dba)3] in Suzuki–Miyaura C–C coupling reactions for the atropselective synthesis of sterically congested biaryls with up to four substituents in the ortho‐positions. The air‐stable catalytic system is excellently suited for the synthesis of tri‐ortho‐substituted biaryls under mild conditions (0.1 mol‐%, 50–100 °C).