Diastereo- and Enantioselective Cross-Couplings of Secondary Alkylcopper Reagents with 3-Halogeno-Unsaturated Carbonyl Derivatives

Kremsmair, Alexander; Skotnitzki, Juri und Knochel, Paul (2020): Diastereo- and Enantioselective Cross-Couplings of Secondary Alkylcopper Reagents with 3-Halogeno-Unsaturated Carbonyl Derivatives. In: Chemistry-A European Journal, Bd. 26, Nr. 52: S. 11971-11973

Abstract

Chiral secondary alkylcopper reagents were prepared from the corresponding alkyl iodides with retention of configuration by an I/Li-exchange usingtBuLi (-100 degrees C, 1 min) followed by a transmetalation with CuBr.P(OEt)(3)(-100 degrees C, 20 s). These stereodefined secondary alkylcoppers underwent stereoretentive cross-couplings with several 3-iodo or 3-bromo unsaturated carbonyl derivatives leading to the corresponding gamma-methylated Michael acceptors in good yields and with high diastereoselectivities (dr up to 96:4). The method was extended to enantiomerically enriched alkylcoppers, providing optically enriched advanced natural product intermediates with up to 90 %ee.

• Dokumententyp: Zeitschriftenartikel
• Fakultät: Chemie und Pharmazie > Department Chemie
• Themengebiete: 500 Naturwissenschaften und Mathematik > 540 Chemie
• ISSN: 0947-6539
• Sprache: Englisch