Direct catalytic asymmetric synthesis of highly functionalized tetronic acids/tetrahydro-isobenzofuran-1,5-diones via combination of cascade three-component reductive alkylations and Michael-aldol reactions
作者:Dhevalapally B. Ramachary、Mamillapalli Kishor
DOI:10.1039/c003588b
日期:——
A practical and sustainable chemical process for the synthesis of highly substituted tetrahydro-isobenzofuran-1,5-diones was achieved for the first time through asymmetric cascade Michael-aldol reaction of 4-hydroxy-3-alkyl-5H-furan-2-ones with alkyl vinyl ketones in the presence of a catalytic amount of L-proline or 9-amino-9-deoxyepiquinine/TCA. In this article, we discovered for the first time the
Copper complex protection in the regioselective alkylation of methyl 3,5-dioxohexanoate. Preparation of 3-alkyl derivatives of 4-hydroxy-6-methyl-2-pyrone
Protection of the diketone moiety of the polyketide model methyl 3,5-dioxohexanoate by copper(II) complex formation followed by alkylation of the free C-2 position results in overall regioselectivealkylation of the diketoester to afford methyl 2-alkyl-3,5-dioxohexanoates, which under cyclization afford 3-alkyl derivatives of triacetic acid lactone.
Diaminocyclopentadienone Ruthenium Complex Catalyzed Alkylation of Indoles and Ketones with Primary Alcohols
作者:Steffen Skowaisa、Edgar Haak
DOI:10.1002/ejoc.202300707
日期:——
The borrowing hydrogen approach allows the direct utilization of non-activated alcohols as alkylating agents. A readily available, air and moisture stable ruthenium complex proves to be a particularly effective hydrogen autotransfer catalyst for the alkylation of various indoles or ketones with poorly reactive alcohols.