Phosphine-catalysed (4+1) annulations of β′-acetoxy allenoate with β,γ-unsaturated carbonyl compounds
作者:Yueqi Zhang、Danfeng Wang、Xiaofeng Tong
DOI:10.1039/d1cc00368b
日期:——
While β,γ-unsaturatedcarbonylcompounds have been widely used as γC- or αC-nucleophiles, their potential αC,αC-bisnucleophilic reactivity is still underdeveloped. Herein, a phosphine-catalysed (4+1) annulation of β′-acetoxy allenoate and a β,γ-unsaturatedcarbonylcompound is reported, wherein β′-acetoxy allenoate is the 1,4-biselectrophilic component while the β,γ-unsaturatedcarbonylcompound serves
Organocatalytic Diastereodivergent Enantioselective Formal oxa‐Diels‐Alder Reaction of Unsaturated Ketones with Enoates Under Liquid‐Assisted Grinding Conditions
A LAG to stand on: Liquid-assisted grinding (LAG) allows enantioselective and diastereodivergent construction of chiral pyran derivatives. The formal oxa-Diels-Alder reaction can be directed towards diastereomers by using either mono- or bifunctional organocatalysts.
chemodivergent [4 + 1] and [3 + 3] annulations of allenyl imides and β,γ-enones have been developed, furnishing highly substituted 2-cyclopentenone and 2-pyranone derivatives in moderate to excellent yields. Two plausible reaction mechanisms involving two different ketene intermediates have been proposed to explain the observed chemoselectivity. Moreover, by virtue of the α,β-enone substructure of the [4 + 1]