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The Enantioselective Synthesis of 3-Methoxy-1, 3, 5 (10)-estratrien-11, 17-dione by a Thermal Intramolecular Cycloaddition Reaction. Preliminary communication

✍ Scribed by Wolfgang Oppolzer; Kurt Bättig; Martin Petrzilka

Publisher: John Wiley and Sons
Year: 1978
Tongue: German
Weight: 189 KB
Volume: 61
Category: Article
ISSN: 0018-019X
DOI: 10.1002/hlca.19780610535

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✦ Synopsis

Abstract

The enantiomerically pure (+)‐3‐methoxy‐1, 3, 5 (10)‐estratrien‐11, 17‐dione 11 (with trans‐anti‐trans configuration) was synthesized in a highly stereocontrolled fashion from (±)‐t‐butyl 4‐methoxy‐1‐benzocyclobutene carboxylate (8) and the (+)‐carboxylic acid 6, obtained from 4 in two steps, followed by one crystallization of the (+)‐ephedrine salt. The key step 10→11 (Scheme 2) involves a thermal intramolecular cycloaddition reaction.

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