The highly enantioselective hydrogenation of 3-aryl-2H-1,4-benzoxazines was achieved using the (cyclooctadiene)iridium chloride dimer/(S)-SegPhos/iodine [Ir(COD)Cl]2/(S)-SegPhos/I2} system as catalyst with up to 92% ee. The 3-styryl-2H-1,4-benzoxazine derivatives were also hydrogenated by the iridium catalyst and Pd/C in two consecutive steps whereby 93–95% ee values were obtained.
使用(环辛二烯)铱氯化二聚物/(S)-SegPhos /碘[Ir(COD)Cl] 2 /(S)-SegPhos实现对3-芳基2 H -1,4-苯并恶嗪的高度对映选择性氢化/ I 2 }体系作为催化剂,ee最高可达92%。3-styryl-2 H -1,4-苯并恶嗪衍生物还通过铱催化剂和Pd / C在两个连续的步骤中进行氢化,从而获得93-95%ee值。
Rhodium(<scp>iii</scp>)-catalyzed intermolecular [3+3] annulation of benzoxazines with quinone compounds: access to spiro-heterocyclic scaffolds
作者:Qing-Yi Wei、Ze Zhou、Meng-Lian Yao、Ji-Kai Liu、Bin Wu、Jin-Ming Yang
DOI:10.1039/d3cc03609j
日期:——
A rhodium(III)-catalyzed redox-neutral spiroannulation approach to access the spiro[benzo[b][1,4]oxazine-benzo[c]chromene skeleton is described in this contribution. A variety of spiro[5.5]-heterocyclic scaffolds were obtained in moderate to excellent yields under mild conditions. Key features of this protocol are good substrate scope, silver-free conditions, low catalyst loadings, easy handling under
本文描述了一种铑( III )催化的氧化还原中性螺环化方法来获得螺[苯并[ b ][1,4]恶嗪-苯并[ c ]色烯骨架。在温和条件下以中等至优异的产率获得了多种螺[5.5]-杂环支架。该方案的主要特点是良好的底物范围、无银条件、低催化剂负载量、在空气下易于处理和 100% 原子经济性。此外,放大反应和后期衍生化凸显了该方法的潜在合成效用。