Stereoselective Barbier-Type Allylations and Propargylations Mediated by CpTiCl<sub>3</sub>
作者:Josefa L. López-Martínez、Irene Torres-García、Ignacio Rodríguez-García、Manuel Muñoz-Dorado、Miriam Álvarez-Corral
DOI:10.1021/acs.joc.8b02643
日期:2019.1.18
CpTiCl2, prepared in situ by manganese reduction of CpTiCl3, is an excellent new system for the Barbier-typeallylation and propargylation of carbonyl compounds. It can be used in catalytic amounts when combined with Et3N·HBr/TMSBr, which acts as a regenerating system. The high regio- and stereoselectivity shown by this system makes it useful for prenylation and crotylation processes in the synthesis
Isoprene reacts with aldehydes in the presence of a catalytic amount of Pd(OAc)2–4PPh3 or Pd(PPh3)4 and a stoichiometric amount of SnCl2 at 40–50 °C in AcOH–H2O to produce 1-substituted 2,2-dimethyl-3-buten-1-ols regioselectively.
Highly Regioselective and Stereoselective Allylation of Aldehydes via Palladium-Catalyzed in Situ Hydrostannylation of Allenes
作者:Hao-Ming Chang、Chien-Hong Cheng
DOI:10.1021/ol0064563
日期:2000.11.1
regio- and stereoselective allylation of aldehydes by allenes proceeds smoothly in aqueous/organic media in the presence of PdCl(2)(PPh(3))(2), HCl, and SnCl(2). The reaction likely occurs via hydrostannylation of allenes and allylation of aldehydes by the in situ generated allyltrichlorotins to afford the final products.