Premium
Collective Total Synthesis of Englerin A and B, Orientalol E and F, and Oxyphyllol: Application of the Organocatalytic [4+3] Cycloaddition Reaction
Author(s) -
Wang Jie,
Chen ShuGuang,
Sun BingFeng,
Lin GuoQiang,
Shang YongJia
Publication year - 2013
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201203467
Subject(s) - cycloaddition , total synthesis , stereoselectivity , intramolecular force , chemistry , regioselectivity , stereochemistry , natural product , allylic rearrangement , combinatorial chemistry , catalysis , organic chemistry
The concise collective total synthesis of englerin A and B, orientalol E and F, and oxyphyllol has been accomplished in 10–15 steps, with the total synthesis of orientalol E 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 epoxidation–S N 2′ 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 orientalol E. 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 orientalol E, 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).