The Preparation of α-Alkylidene-γ-Butyrolactones Using a Telescoped Intramolecular Michael/Olefination (TIMO) Sequence: Synthesis of (+)-Paeonilactone B
作者:Michael G. Edwards、Martin N. Kenworthy、Russell R. A. Kitson、Alexis Perry、Mark S. Scott、Adrian C. Whitwood、Richard J. K. Taylor
DOI:10.1002/ejoc.200800558
日期:2008.10
A novel telescopedintramolecularMichael addition/proton transfer/HWE olefination sequence has been developed to provide rapid access to α-alkylidene-γ-butyrolactones. This methodology has been applied to prepare a range of tetrahydrobenzofuran-2,5-diones, and related systems, and also utilised in an extremely short synthesis of the natural product (+)-paeonilactoneB in enantiomerically pure form
The eight novel ivangustin enantiomer analogues possessing alpha-methylene-gamma-butyrolactone moiety have been synthesized using (4S6R, 4S6S)-4-tert-butyldimethylsilyloxy-6-methylcyclohex-2-en-1-one (1) as starting material. These transformations were mainly carried out by aldol condensation reaction and one-pot annelation procedure. The stereochemistry of these synthesized analogues was determined by NOE analysis. Their cytoxicity was evaluated against the human cancer cell lines HCT-116 (colon), HL-60 (leukemia), QGY-7701 (liver), SMMC-7721 (liver), A549 (lung), MCF-7 (breast). The results showed that these analogues were more selective against the cell lines HL-60 and QGY-7701. Analogue 17 exhibited potent cytotoxicity and high selectivity toward HL-60 cell line with IC50 value of 1.02 mu M, which suggested that it might be a promising anti-cancer lead compound. The inhibitory activities against NO production and the cytotoxicities in RAW 264.7 macrophages were determined at the same time. All of the analogues significantly inhibited the NO production with IC50 value in the range of 3.44-6.99 mu M. Analogues 17, 22, 23 and 7 showed higher cytotoxicities, indicated their inhibitory activities against NO production may be influenced by the cytotoxicities. (C) 2015 Elsevier Masson SAS. All rights reserved.