Chemoselective Umpolung of Enals for Asymmetric Homoenolate Cross-Annulation of Enals and Aldehydes Catalyzed by N-Heterocyclic Carbene
作者:Ryuji Ide、Ryuji Kyan、Thien Phuc Le、Yuya Kitagawa、Kohei Sato、Nobuyuki Mase、Tetsuo Narumi
DOI:10.1021/acs.orglett.9b03509
日期:2019.11.15
An asymmetric homoenolate cross-annulation of enals and aldehydes with high enantioselectivity is realized by NHC-catalyzed chemoselective umpolung of enals. The reaction proceeds in a highly chemoselective manner, selectively generating the conjugated Breslow intermediates from enals rather than aldehydes, enabling the homoenolate addition of enals to aldehydes in preference to competing acyl anion-mediated
通过NHC催化的化学对映体的化学选择,实现了对映体和醛类的不对称均烯酸酯交叉环化,具有很高的对映体选择性。该反应以高度化学选择性的方式进行,从烯醛而不是醛选择性地产生共轭的Breslow中间体,从而使烯醛均烯酸酯加成到醛中,而不是竞争性的阴离子阴离子介导的反应。以高收率和高对映选择性形成富含对映体的取代γ-丁内酯。