Asymmetric Total Synthesis of the Indole Diterpene Alkaloid Paspaline
作者:Robert J. Sharpe、Jeffrey S. Johnson
DOI:10.1021/acs.joc.5b01844
日期:2015.10.2
An enantioselective synthesis of the indole diterpenoid natural product paspaline is disclosed. Critical to this approach was the implementation of stereoselective desymmetrization reactions to assemble key stereocenters of the molecule. The design and execution of these tactics are described in detail, and a thorough analysis of observed outcomes is presented, ultimately providing the title compound
A Practical and Catalytic Reductive Olefin Coupling
作者:Julian C. Lo、Yuki Yabe、Phil S. Baran
DOI:10.1021/ja4117632
日期:2014.1.29
A redox-economic method for the direct coupling of olefins that uses an inexpensive iron catalyst and a silane reducing agent is reported. Thus, unactivated olefins can be joined directly to electron-deficient olefins in both intra- and intermolecular settings to generate hindered bicyclic systems, vicinal quaternary centers, and even cyclopropanes in good yield. The reaction is not sensitive to oxygen
Electrophilic Allylations and Benzylations of Indoles in Neutral Aqueous or Alcoholic Solutions
作者:Martin Westermaier、Herbert Mayr
DOI:10.1021/ol0618555
日期:2006.10.1
[reaction: see text] Indoles are allylated and benzylated in moderate to quantitative yield when stirred with allyl and benzyl halides in 80% aqueous acetone in the presence of NH(4)HCO(3) at room temperature.
The basic industrial feedstock isoprene was employed as a building block to install prenyl and reverse‐prenyl groups onto indoles. The regioselectivity can be manipulated by the choice of metal hydride. Reverse‐prenylated indoles were attained with high selectivity when using Rh−H. By switching to a Pd−H catalyst, selectivity toward prenylated indoles was achieved. This regiodivergent method also features
Isoprene: A Promising Coupling Partner in C–H Functionalizations
作者:Qing-An Chen、Wei-Song Zhang、Yan-Cheng Hu
DOI:10.1055/s-0040-1707172
日期:2020.10
basic industrial feedstock isoprene is an ideal alternative precursor. However, given that electronically unbiased isoprene might undergo six possible addition modes in the coupling reactions, it is difficult to control the selectivity. This article summarizes the strategies we have developed to achieve regioselective C–H functionalizations of isoprene under transition-metal and acid catalysis. 1 Introduction