Single-Flask Multicomponent Synthesis of Highly Substituted α-Pyrones via a Sequential Enolate Arylation and Alkenylation Strategy
作者:Michael Grigalunas、Olaf Wiest、Paul Helquist
DOI:10.1021/acs.orglett.6b02969
日期:2016.11.4
Trisubstituted α-pyrones are obtained by a Pd-catalyzed three-component, single-flask operation via an α-arylation, subsequent α-alkenylation, alkene isomerization, and dienolate lactonization. A variety of coupling components under mild conditions afforded isolated yields of up to 93% of the pyrones with complete control of regioselectivity. Metal dependence was noted for three of the steps of the
Stereoselective Preparationof Functionalized Unsaturated Lactones and Esters via FunctionalizedMagnesium Carbenoids
作者:Paul Knochel、Viet Anh Vu、Ilan Marek
DOI:10.1055/s-2003-41035
日期:——
The reaction of β,β-dibromo or diiodo unsaturatedesters with i-PrMgCl (1 equivalent) indiethyl ether allows the generation of functionalized alkenylmagnesiumcarbenoids which react with retention of configuration with variouselectrophiles providing polyfunctionalized unsaturated esters andlactones. By using two equivalents of i-PrMgCl,a 1,2-migration with retention of configuration occurs in diethylether allowing a new synthesis of tetrasubstituted esters and lactones.