Synthese von Östronderivaten aus Siloxycyclopropancarbonsäureestern

✍ Scribed by Schnaubelt, Jürgen ;Zschiesche, Ruth ;Reißgi, Hans-Ulrich ;Lindner, Hans Jörg ;Richter, Jens

• Book ID: 102900949
• Publisher: John Wiley and Sons
• Year: 1993
• Tongue: English
• Weight: 979 KB
• Volume: 1993
• Category: Article
• ISSN: 0947-3440
• DOI: 10.1002/jlac.199319930111

✦ Synopsis

Synthese of Estrone Derivatives from Siloxycyclopropanecarboxylic Acid Esters

Syntheses of new rac‐estrone analogues such as 10, 19, 21 and 22 are reported. Key intermediate 3 has been efficiently prepared by alkylation of the lithium enolate of the methyl cyclopropanecarboxylate 1 employing 2 as electrophile. One‐pot ring opening/Michael addition procedures have been developed to convert 1 and 3 into polyfunctionalized compounds 5, 7, 8, and 9. Diketo diester 8 can be cyclized with acid to give tetracyclic dienes which are immediately reduced by triethylsilane under acidic conditions providing steroid derivatives 10 and 11. Depending on the purification method, in addition to 10/11 the isomer 12 and the oxidized products 13/14 have been isolated. The structures of 10 and 13 have been confirmed by X‐ray analyses. Acid‐induced cyclization of precursor 9 affords the tetracyclic diene 19 and the pentacyclic lactone 20. Catalytic hydrogenation of the diene 19 provides the estrone derivative 21 in good yield, but with the unnatural cis‐C/D‐ring junction. Ionic reduction of 19 gives the steroid derivative 22 together with the alcohols 23.