Stereoselective Synthesis of Axially Chiral Natural Products, (−)-Steganone and O,O′-Dimethylkorupensamine A, Utilizing Planar Chiral (Arene)chromium Complexes

✍ Scribed by Ken Kamikawa; Takashi Watanabe; Akira Daimon; Motokazu Uemura

• Book ID: 104209854
• Publisher: Elsevier Science
• Year: 2000
• Tongue: French
• Weight: 425 KB
• Volume: 56
• Category: Article
• ISSN: 0040-4020
• DOI: 10.1016/s0040-4020(99)01115-1

✦ Synopsis

AbstractÐPalladium(0)-mediated Suzuki±Miyaura cross-coupling of planar chiral (2,6-disubstituted bromobenzene)chromium complexes with o-substituted arylboronic acids in the presence of sodium carbonate under re¯uxing in aqueous methanol gave stereoselectively axially chiral mono Cr(CO) 3 -complexed biaryls. The axial stereochemistry of the cross-coupling products was found to be largely dependent on the steric bulkiness of ortho substituent of arylboronic acids and reaction conditions. The cross-coupling with o-alkyl or hydroxymethyl substituted arylboronic acids gave kinetically controlled products in which the ortho substituents were oriented in syn-con®guration to the tricarbonylchromium fragment. On the other hand, o-formyl phenylboronic acid produced thermodynamically stable anti-coupling products under the same conditions. By utilizing these methodologies, biologically active axially chiral natural products, (2)-steganone and O,O H -dimethyl derivative of the natural product of korupensamine A, were stereoselectively synthesized.