期刊
TETRAHEDRON
卷 56, 期 15, 页码 2325-2337出版社
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/S0040-4020(99)01115-1
关键词
alkaloids; atropisomerism; chromium and compounds; coupling reactions
Palladium(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 refluxing 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-configuration 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, (-)-steganone and O,O-1-dimethyl derivative of the natural product of korupensamine A, were stereoselectively synthesized. (C) 2000 Elsevier Science Ltd. All rights reserved.
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