Synthesis of a Novel Enantiopure Spiro-B-norestradiol Analogue by Multiple Pd-Catalyzed Transformations

✍ Scribed by Lutz F. Tietze; J. Matthias Wiegand; Carsten A. Vock

• Publisher: John Wiley and Sons
• Year: 2004
• Tongue: English
• Weight: 150 KB
• Volume: 2004
• Category: Article
• ISSN: 1434-193X
• DOI: 10.1002/ejoc.200400263

✦ Synopsis

Abstract

The novel tetracyclic spiro compound 13 was synthesized by the use of two subsequent Pd‐catalyzed reactions. Firstly, the ortho‐bromobenzyl chloride 1 was coupled with the enantiopure boronic ester 8, obtained from the Hajos−Wiechert ketone in a chemoselective Suzuki‐type reaction to give 12 in 77% yield. Unexpectedly, the intramolecular Heck reaction then did not provide the annulated compound 6, but the spirocyclic compound 13, containing a quaternary carbon center, in 73% yield. The Heck reaction was also performed under microwave irradiation conditions, allowing a considerably shorter reaction time. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)