Synthesis of Highly Functionalized 9,10-Phenanthrenequinones by Oxidative Coupling Using MoCl5
摘要:
The strong oxidative power of molybdenum pentachloride gives rise to an efficient oxidative C-C bond formation of benzil derivatives to the corresponding 9,10-phenanthrenequinones. A highly complementary method to previous approaches was developed. The required derivatives are accessible in a modular fashion and in excellent yields. By this approach the orchid-derived natural product cypripediquinone A was synthesized for the first time.
Synthesis of Highly Functionalized 9,10-Phenanthrenequinones by Oxidative Coupling Using MoCl5
摘要:
The strong oxidative power of molybdenum pentachloride gives rise to an efficient oxidative C-C bond formation of benzil derivatives to the corresponding 9,10-phenanthrenequinones. A highly complementary method to previous approaches was developed. The required derivatives are accessible in a modular fashion and in excellent yields. By this approach the orchid-derived natural product cypripediquinone A was synthesized for the first time.
One-pot hydrosilylation–protodesilylation of functionalized diarylalkynes: a highly selective access to Z-stilbenes. Application to the synthesis of combretastatin A-4
An efficient stereoselective synthesis of Z-stilbenes has been developed from diarylalkynes via a new hydrosilylation-protodesilylation process. The scope and limitation of this method is presented to stereo selectively prepare a wide range of (Z)-stilbenes in a one-pot way is presented. A concise application to the preparation of combretastatin A-4 (CA-4), a vascular targeting agent inhibitor of tubulin polymerisation is described. (C) 2007 Elsevier Ltd. All rights reserved.
Synthesis and antitumor activity of benzils related to combretastatin A-4
A series of benzil derivatives related to combretastatin A-4 (CA-4) have been synthesized by oxidation of diarylalkynes promoted by PdI2 in DMSO. Using this new protocol, 14 benzils were prepared in good to excellent yields and their biological activity has been delineated. Several benzils exhibited excellent antiproliferative activity: for example, 4j and 4k bearing the greatest resemblance to CA-4 and AVE-8062, respectively, were found to inhibit cell growth at the nanomolar level (20-50 nM) on four human tumor cell lines. Flow cytometric analysis indicates that these compounds act as antimitotics and arrest the cell cycle in G(2)/M phase. A cell-based assay indicated that compounds 4j and 4k displayed a similar inhibition of tubulin assembly with an IC50 value similar to CA-4. These results clearly demonstrated that the Z-double bond of CA-4 can be replaced by a 1,2-diketone unit without significant loss of cytotoxicity and inhibition of tubulin assembly potency. (C) 2008 Elsevier Ltd. All rights reserved.