Novel concepts in directed biaryl synthesis, XXXVII. Synthesis and enantiomerization of a nonracemic 2-hydroxy-2′-biarylcarbaldehyde, a probable intermediate in the atropo-enantioselective ring opening of biaryl lactones

✍ Scribed by Bringmann, Gerhard ;Hartung, Thomas

• Publisher: John Wiley and Sons
• Year: 1994
• Tongue: English
• Weight: 401 KB
• Volume: 1994
• Category: Article
• ISSN: 0947-3440
• DOI: 10.1002/jlac.199419940314

✦ Synopsis

Abstract

The directed preparation of a “free”, i.e. nonprotected biaryl with a phenolic OH function and a formyl group in opposite ortho positions, in a nonracemic form, is described. The free activation barrier ΔG^≠^ for the atropisomerization, which was determined to be 99.2 kJ mol^−1^, is far lower than expected for an exclusively physical rotation process and is more likely in agreement with an isomerization via lactol‐type cyclic intermediates previously postulated. magnified image