Asymmetric Synthesis of Tertiary 2-Substituted 5-Oxotetrahydrofuran-2-carboxylic Acids
摘要:
3-Substituted 1,2-cyclopentanediones 1 were transformed to 2-substituted 5-oxotetrahydrofuran-2-carboxylic acids 2 using a catalytic process with 0.2-0.3 equivalent of Ti(OiPr)(4)/tartaric ester/tBuO0H complex in up to 72% isolated yield and up to 94% ee. Different functional groups in the 3-alkyl substituent of 1 like, hydroxy, ether, Boc-amino and ester groups are tolerated. Boc-aminomethyl substitu.ents lead to beta-amino acid analogues and Boc-aminoethyl substituent to gamma-amino acid analogues as well as spiro-lactonelactams. A direct, two-step procedure for homocitric acid synthesis is described.
A series of novelacyclic thymine nucleoside analogues were prepared by the Mitsunobu reaction from appropriately protected chiral triols. The enantiomeric triols were obtained from substituted γ-lactone acids, prepared by asymmetric oxidation of 3-substituted-1,2-cyclopentanediones. The cytotoxic activity of new analogues was evaluated on MCF-7 human breast cancer and HeLa cells, and antiviral activities
3-Alkyl-1,2-cyclopentanediones 1 are transformed into 2-alkyl-2-hydroxyglutaric acid gamma-lactones 3 in up to 83% isolated yields and up to 96% ee, affording a simple access to many bioactive compounds, including diacylglycerol lactones (DAG-lactones). (c) 2006 Elsevier Ltd. All rights reserved.