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Diastereo‐ and Enantioselective Cross‐Couplings of Secondary Alkylcopper Reagents with 3‐Halogeno‐Unsaturated Carbonyl Derivatives
Author(s) -
Kremsmair Alexander,
Skotnitzki Juri,
Knochel Paul
Publication year - 2020
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.202002297
Subject(s) - transmetalation , reagent , enantioselective synthesis , chemistry , alkyl , natural product , medicinal chemistry , organic chemistry , stereochemistry , catalysis
Chiral secondary alkylcopper reagents were prepared from the corresponding alkyl iodides with retention of configuration by an I/Li‐exchange using t BuLi (−100 °C, 1 min) followed by a transmetalation with CuBr ⋅ P(OEt) 3 (−100 °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 γ‐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 .