Stereoselective Csp
<sup>3</sup>
−Csp
<sup>2</sup>
Cross‐Couplings of Chiral Secondary Alkylzinc Reagents with Alkenyl and Aryl Halides
作者:Juri Skotnitzki、Alexander Kremsmair、Daniel Keefer、Ye Gong、Regina Vivie‐Riedle、Paul Knochel
DOI:10.1002/anie.201910397
日期:2020.1.2
We report palladium-catalyzed cross-coupling reactions of chiral secondary non-stabilized dialkylzinc reagents, prepared from readily available chiral secondary alkyl iodides, with alkenyl and aryl halides. This method provides α-chiral alkenes and arenes with very high retention of configuration (dr up to 98:2) and satisfactory overall yields (up to 76 % for 3 reaction steps). The configurational stability
我们报告了手性仲非稳定的二烷基锌试剂的钯催化交叉偶联反应,该试剂由易于获得的手性仲烷基碘与烯基和芳基卤化物制备。该方法提供的α-手性烯烃和芳烃具有很高的构型保留率(dr高达98:2)和令人满意的总收率(3个反应步骤高达76%)。确定了这些手性不稳定的二烷基锌试剂的构型稳定性,并在25°C下超过了数小时。进行DFT计算以合理化催化循环中的立体保留。此外,在绝对立体化学的控制下,交叉偶联反应用于倍半萜(S)-和(R)-姜黄素的有效全合成中。