developed. A variety of eight-membered cyclic ethers with two contiguous tertiary stereocenters were obtained in high yields with excellent stereoselectivities. This reaction not only provides a new strategy for constructing enantioenriched eight-membered cyclic ethers but also demonstrates the practicability of ynones as C4-syntons for the synthesis of chiral medium-membered rings.
synthesis. Here, by combining the squaramide and DBU catalysis, a sequential asymmetric conjugate addition/cyclization reaction between benzofuran-derived azadienes and ynones has been well-developed, providing straightforward access to chiral eight-membered N-heterocycles in high yields with stereoselectivities. This protocol features the use of a bifunctionalsquaramide catalyst for controlling the enantioselectivity
八元N-杂环的对映选择性合成是有机合成中长期存在的挑战。在这里,通过结合方酰胺和 DBU 催化,苯并呋喃衍生的氮杂二烯和炔酮之间的连续不对称共轭加成/环化反应已经得到很好的发展,提供了以高产率和立体选择性直接获得手性八元 N 杂环的方法。该方案采用双功能方酰胺催化剂控制产物的对映选择性,同时利用DBU实现分子内环化,提高产物的非对映选择性。
Palladium-catalyzed carbonylative coupling of benzyl chlorides with terminal alkynes to give 1,4-diaryl-3-butyn-2-ones and related furanones
作者:Xiao-Feng Wu、Helfried Neumann、Matthias Beller
DOI:10.1039/c1ob06345f
日期:——
A general palladium-catalyzed carbonylative Sonogashira coupling of benzyl chlorides with terminal acetylenes has been established. Depending on the alkyne 1,4-diaryl-3-butyn-2-ones or substituted furanones are obtained in moderate to good yields. Best catalytic performance is achieved applying a mixed Pd(PPh3)Cl2/P(OPh)3 catalyst system.
Stereoselective Synthesis of Polysubstituted Conjugated Dienes Enabled by Photo‐driven Sequential Sigmatropic Rearrangement
作者:Xin Ji、Chaoren Shen、Yuhao Ni、Zhi-Yao Si Si、Yuzhu Wang、Xinrong Zhi、Yuting Zhao、Huiling Peng、Lu Liu
DOI:10.1002/anie.202400805
日期:——
An unprecedented photo-driven quadruple sequential sigmatropic rearrangements of α-aryl α-diazo alkynylketones with aminals via 1,6-dipolar ion intermediate is disclosed. This protocol provides a facile access to synthetically useful multi-substituted conjugated dienes in highly stereoselective manner via visible light catalysis in mild conditions.