Stereoselektive Synthese des substituierten Morphan-Gerüstes ausgehend von 4-Acetamidocyclohexanon

✍ Scribed by Teuber, Hans-Joachim ;Tsaklakidis, Christos ;Bats, Jan Willem

• Book ID: 102901326
• Publisher: John Wiley and Sons
• Year: 1990
• Tongue: English
• Weight: 757 KB
• Volume: 1990
• Category: Article
• ISSN: 0947-3440
• DOI: 10.1002/jlac.1990199001146

✦ Synopsis

Stereoselective Synthesis of the Substituted Morphane Framework Starting with 4‐Acetamidocyclohexanone

4‐Acetamidocyclohexanone (2), prepared from 4‐acetamido‐cyclohexanol (1), has been transformed into the ethyleneacetal 3b which was amidated with pyruvic and 2‐oxobutyric acid to give 3c and d, respectively. After removal of the protecting group (4a, b) the amide is treated with sodium hydride in tetrahydrofuran or with sodium ethylate in ethanol. Depending on the reaction conditions 4b is transformed into the aldol 6 or the cyclised aldol 5b (5a from 4a, respectively) with 2‐azabicyclo[3.3.1]nonane structure and endo‐positioned hydroxy group. Constitution and stereochemistry has been proved by X‐ray structure analysis of 7a. The stereochemistry of the ring closure reaction corresponds to the transition state postulated.