Simple regioselective synthesis of trans-7a-methylhydrind-4-en-1-one, a key intermediate for steroid total synthesis

✍ Scribed by Michael E. Jung; Kim M. Halweg

• Book ID: 104234361
• Publisher: Elsevier Science
• Year: 1981
• Tongue: French
• Weight: 249 KB
• Volume: 22
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(01)82029-3

✦ Synopsis

__II__-.-. Intramolecular Diels-Alder cycloaddition and hydrolysis of the ketals 11 and 12, derived from the trienone 6, afforded mainly the trans-hydrindenone 8a _* The last few years have witnessed a great upsurge in interest in the development of new methods for the total synthesis of steroids.4 Most of the new routes have been designed to produce A-ring aromatic steroids such as estrone, 5 although a few have been aimed at the more medicinally interesting corticosteroid group, e.g., cortisone 1. 6 We report here a very simple method for the stereoselective preparation of the key trans C,D-ring intermediate &la_ for the total synthesis of steroids. For some time, we have envisioned the approach shown retrosynthetically in Scheme I, namely the preparation of cortisone 1 by standard methods from the dione 2. which could itself be produced from a Diels-Alder reaction of the diene J7 with the hydrindenedione 4.