| |
[摘要]：The concise collective total synthesis of englerinA and B, orientalolE and F, and oxyphyllol has been accomplished in 1015 steps, with the total synthesis of orientalolE and oxyphyllol being achieved for the first time. The success obtained was enabled by the realization of the [4+3] cycloaddition reaction of 9 and 10. Other features of the synthesis include 1)the intramolecular Heck reaction to access the azulene core, 2)the epoxidationSN2 reduction sequence to access the allylic alcohol, 3)the efficient regioselective and stereoselective formal hydration of the bridging CC bond in the synthesis of englerins, and 4)the late-stage chemo- and stereoselective CH oxidation in the synthesis of orientalolE. The total synthesis of these natural products has enabled the structural revision of oxyphyllol and established the absolute stereochemical features of the organocatalytic [4+3] cycloaddition reaction. The identification of 5 as the natural product oxyphyllol, the success in converting 5 to orientalolE, along with the fact that englerins and oxyphyllol were isolated from plants of the same genus Phyllanthus gives support to our proposed biosynthetic pathways. This work may enable detailed biological evaluations of these natural products and their analogues and derivatives, especially of their potential in the fight against renal cell carcinoma (RCC). |
|
