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

ABSTRACT: Chiral secondary alkylcopper reagents were prepared from the corresponding alkyl iodides with retention of configuration by an I/Li-exchange using tBuLi (-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.

SUBMITTER: Kremsmair A

PROVIDER: S-EPMC7540566 | biostudies-literature | 2020 Sep

REPOSITORIES: biostudies-literature

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

Kremsmair Alexander A Skotnitzki Juri J Knochel Paul P

Chemistry (Weinheim an der Bergstrasse, Germany) 20200902 52

Chiral secondary alkylcopper reagents were prepared from the corresponding alkyl iodides with retention of configuration by an I/Li-exchange using tBuLi (-100 °C, 1 min) followed by a transmetalation with CuBr⋅P(OEt)<sub>3</sub> (-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 diastereoselecti ...[more]

PMID: 32557902

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