Efficient Homologation of Aldehydes to 2,4,6-Alkatrienals by means of an α-(1,3-Dioxenylallyl)boronate
作者:Reinhard W. Hoffmann、Frank Schäfer、Eckart Haeberlin、Thorsten Rohde、Karsten Körber
DOI:10.1055/s-2000-8720
日期:——
The α-dioxenyl-allylboronate 4 allows the direct conversion of aldehydes into the 7-hydroxy-2,4-dienals (6). The latter compounds can be dehydrated to 2,4,6-alkatrienals 7 by means of the Burgess reagent or methanesulfonyl anhydride/Hünig Base.
Syntheses of new lithio hexavinylogation reagents are described starting either from ω-bromo polyenacetal, ω-bromo polyenol ether or ω-bromo non conjugated aldehyde. The reactivity of the lithio reagents has been tested by condensation with benzaldehyde; the resulting hexaenal has been obtained in a one or two steps procedure.