Tandem Blaise/retro-Blaise Reaction for the Nitrile-Mediated Regioselective Intermolecular Addition of Unstabilized Zinc Ester Enolates (Reformatsky Reagents) to 1-Alkynes and 1,3-Enynes
作者:Ju Hyun Kim、Yu Sung Chun、Sang-gi Lee
DOI:10.1021/jo402015n
日期:2013.11.15
of a nitrile as a mediator to achieve the regioselective intermolecular addition of unstabilized zinc ester enolates (Reformatskyreagents) to 1-alkynes and 1,3-enynes. This reaction is made possible by a reversible addition of enolates to a nitrile (Blaise reaction), generating a zinc aza-enolate that, unlike zinc ester enolates, can add intermolecularly to 1-alkynes and 1,3-enynes. Subsequent removal
robust, and stereocomplementary synthesis of fully-substituted (E)- and (Z)-stereodefined α,β-unsaturated esters 3 from accessible α-substituted β-ketoesters 1via (E)- and (Z)-enol phosphonates was achieved. The present method involves two accessible reaction sequences: (i) (E)- and (Z)-stereocomplementary enol phosphorylations of a wide variety of β-ketoesters 1 (24 examples; 71–99% yield, each >95 : 5
Unlocking the Asymmetric Hydrogenation of Tetrasubstituted Acyclic Enones
作者:Jorge Faiges、Maria Biosca、Miquel A. Pericàs、Maria Besora、Oscar Pàmies、Montserrat Diéguez
DOI:10.1002/anie.202315872
日期:2024.2.26
Fast and highly selective Ir-catalysts have been developed for the asymmetric hydrogenation of challenging tetrasubstituted acyclicenones. The mechanism and the effects of the catalyst and reaction parameters on selectivity have been unraveled by means of deuterogenation experiments and DFT calculations.
Total Synthesis of Laurane and Guaiane Sesquiterpenoids via Oxidative Nazarov Reaction
作者:Yuye Chen、Wenqing Chen、Zhiting Zhang、Jing Xu
DOI:10.1002/cjoc.202400014
日期:——
natural products, cyclopentenones usually can be fabricated by Nazarov cyclization using divinyl ketones or functionalized tertiary divinyl carbinols (TDCs) as substrates. However, straightforward method for transforming unfunctionalized TDCs to their corresponding cyclopentenones is currently lacking. Herein, we wish to report the total syntheses of four structurally distinct terpenoids, namely laurane-type