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Toward a Total Synthesis of Macrocyclic Jatrophane Diterpenes – Concise Route to a Highly Functionalized Cyclopentane Key Intermediate
Author(s) -
Mulzer Johann,
Giester Gerald,
Gilbert Michael
Publication year - 2005
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.200590124
Subject(s) - chemistry , cyclopentane , total synthesis , annulation , ring (chemistry) , stereochemistry , allylic alcohol , amide , enol , hydroxylation , allylic rearrangement , combinatorial chemistry , organic chemistry , catalysis , enzyme
A total synthesis of the biologically potent jatrophane diterpenes pepluanin A ( 1 ) and euphosalicin A ( 2 ) is being aimed at. En route to these targets, a concise synthesis of the nonracemic cyclopentane building block 74 was developed. Key steps were a Claisen–Eschenmoser rearrangement of the enantiomerically enriched allylic alcohol 14 to amide 34 ( Scheme 7 ), a hydroxy‐lactonization of 40 to 43 ( Scheme 9 ), followed by trans ‐lactonization to 72 , which was subjected to a Davis hydroxylation to 69 ( Scheme 17 ). Eventually, compound 69 was converted into the enol triflate 74 . This material should prove suitable for an annulation of the macrocyclic ring characteristic of the desired jatrophanes 1 and 2 . Less‐successful approaches are also discussed due to their intrinsically valuable information content.