Ynolates were found to react with alpha-alkoxy-, alpha-siloxy-, and alpha-aryloxyketones at room temperature to afford tetrasubstituted olefins with high Z selectivity. Since the geometrical selectivity was determined in the ring opening of the beta-lactone enolate intermediates, the torquoselectivity was controlled by the ethereal oxygen atoms. From experimental and theoretical studies, the high Z
Cu(II)-Catalyzed Acylation by Thiol Esters Under Neutral Conditions: Tandem Acylation-Wittig Reaction Leading to a One-Pot Synthesis of Butenolides
作者:Kazumasa Matsuo、Mitsuru Shindo
DOI:10.1021/ol102407k
日期:2010.11.19
The first catalytic acylation of alcohols with a thiolester present in Wittig reagents under neutral conditions catalyzed by the Cu(II) salt through a push−pull mechanism is reported. Furthermore, a new methodology for the one-pot lactonization of acyloins by a copper catalyst is developed. The synthetic utility of this method for the synthesis of natural products is shown.
Efficient one-step synthesis of trialkylsubstituted 2(5H)-furanones utilizing direct Ti-crossed aldol condensation and its application to the straightforward synthesis of (R)-mintlactone and (R)-menthofuranElectronic supplementary information (ESI) available: calculated structures of 7 and 8. See http://www.rsc.org/suppdata/cc/b2/b208077j/
TiCl4–Bu3N-mediated condensation of ketones with α,α-dimethoxyketones afforded trialkylsubstituted 2(5H)-furanones in a one-pot manner, wherein aldol addition and furanone formation occurred sequentially; its application to straightforward synthesis of (R)-mintlactone and (R)-menthofuran, two representative natural mint perfumes, is demonstrated.