A Highly Regio- and Stereoselective Cascade Annulation of Enals and Benzodi(enone)s Catalyzed by N-Heterocyclic Carbenes
作者:Xinqiang Fang、Kun Jiang、Chong Xing、Lin Hao、Yonggui Robin Chi
DOI:10.1002/anie.201007144
日期:2011.2.18
Three stereogenic centers in a row: The unconventional activation of enal compounds mediated by an N‐heterocyclic carbene (NHC) has generated three consecutive reactive carbon centers that undergo highly regio‐ and stereoselectiveannulations with di(enone)s to generate benzotricyclic products containing multiple stereogenic centers (see scheme).
Dinuclear zinc synergistic catalytic asymmetric phospha-Michael/Michael cascade reaction: synthesis of 1,2,3-trisubstituted indanes bearing phosphoryl groups
作者:Bing-Kai Tao、Hua Yang、Yuan-Zhao Hua、Min-Can Wang
DOI:10.1039/c9ob00544g
日期:——
A new dinuclear zinc synergistic catalytic asymmetric phospha-Michael/Michael cascade reaction of o-dienones and dialkyl phosphates is reported. This method has been proven to be general and efficient for the formation of a range of chiral 1,2,3-trisubstituted indane compounds containing phosphorus groups in good yields (up to 92%) with excellent stereoselectivities (up to >99% ee and up to >99 : 1
报道了新的邻核二烯和磷酸二烷基酯的双核锌协同催化不对称磷酸-迈克尔/迈克尔级联反应。已证明该方法对于形成一系列含磷基团的手性1,2,3-三取代的茚满化合物是普遍有效的,产率高(高达92%),立体选择性好(ee> 99%,最高> 99:1博士)。通过二维(2D)核Overhauser效应光谱1 H– 1 H NMR实验,确定该产品的相对构型具有反式,反式取代模式。提出了一种可能的机制。
Hydrazine Hydrate in Asymmetric Synthesis: A Bifunctional Squaramide Catalytic Approach toward Fused Pyrazolines
作者:Dipankar Das、Chandan Kamilya、Prasanta Ghorai
DOI:10.1021/acs.orglett.3c02529
日期:2023.9.29
developed to utilize hydrazine hydrate in asymmetric organic synthesis by overcoming the rapid background reaction with dienone. The H-bond donor ability of the cinchona-alkaloid-derived squaramide catalyst unlocks this previously deemed infeasibility. The dissymmetric hydrazine addition to symmetrical dienones tolerates various substitutions, resulting in the formation of optically pure fused pyrazoline derivatives