Stereoselective Synthesis of Steroids and Related Compounds, IV. Addition of Cerium Reagents Derived from (Trimethylsilyl)propargyl Bromide to Aldehydes

✍ Scribed by Eckenberg, Peter ;Groth, Ulrich ;Köhler, Thomas

• Publisher: John Wiley and Sons
• Year: 1994
• Tongue: English
• Weight: 606 KB
• Volume: 1994
• Category: Article
• ISSN: 0947-3440
• DOI: 10.1002/jlac.199419940707

✦ Synopsis

Abstract

The addition of (trimethylsilyl)propargylmagnesium bromide (9) to aldehydes afforded predominantly the allenylic alcohols rac‐10. The regioselectivity of this addition changes dramatically when organocerium reagents were used for the addition. In this case nearly exclusive formation of the homopropargylic alcohols rac‐8 was observed. Highest selectivity for this process was obtained when cerium(III) isopropoxide (13) was used as a precursor for the formation of the organocerium reagent. magnified image