The copper-catalyzed [4 + 2] annulation of α,β-unsaturated ketoximeacetates with 1,3-dicarbonyl compounds for the synthesis of three classes of structurally diverse pyridines has been developed. This method employs 1,3-dicarbonyl compounds as C2 synthons and enables the synthesis of multifunctionalized pyridines with diverse electron-withdrawing groups in moderate to good yields. The mechanistic investigation
Tandem Wittig Reaction–Ring Contraction of Cyclobutanes: A Route to Functionalized Cyclopropanecarbaldehydes
作者:Federico Cuccu、Lorenzo Serusi、Alberto Luridiana、Francesco Secci、Pierluigi Caboni、David J. Aitken、Angelo Frongia
DOI:10.1021/acs.orglett.9b02690
日期:2019.10.4
An original tandem reaction consisting of a Wittig reaction-ring contraction process between α-hydroxycyclobutanone and phosphonium ylides has been developed. Highly functionalized cyclopropanecarbaldehydes are obtained in good to high yield.
A one-pot procedure involving radical conjugate addition of B-alkylcatecholboranes to enones followed by intramolecular aldol reaction is reported. Application to the stereoselective synthesis of monocyclic and bicyclic products with up to four contiguous stereogenic centers is presented.
Enantioselective synthesis of 2,3-disubstituted trans-2,3-dihydrobenzofurans using a Brønsted base/thiourea bifunctional catalyst
作者:Diego-Javier Barrios Antúnez、Mark D. Greenhalgh、Charlene Fallan、Alexandra M. Z. Slawin、Andrew D. Smith
DOI:10.1039/c6ob01326k
日期:——
The diastereo- and enantioselectivesynthesis of 2,3-disubstituted trans-2,3-dihydrobenzofuran derivatives (15 examples, up to 96 : 4 dr, 95 : 5 er) via intramolecular Michael addition has been developed using keto–enone substrates and a bifunctional tertiary amine–thiourea catalyst. This methodology was extended to include non-activated ketone pro-nucleophiles for the synthesis of 2,3-disubstituted
has recently been generated from hypervalent iodine precursors via photoredox catalysis. Given the underexplored chemistry of carbyne, due to the paucity of carbyne sources, we are intrigued to discover a new source for this reactive species from classical reagents – phosphonium ylides. Our novel strategy employing phosphonium ylides in an olefin hydrocarbonation reaction features a facile approach