Lewis Acid Catalyzed Tandem 1,4-Conjugate Addition/Cyclization of in Situ Generated Alkynyl <i>o</i>-Quinone Methides and Electron-Rich Phenols: Synthesis of Dioxabicyclo[3.3.1]nonane Skeletons
作者:Ji-Yuan Du、Yan-Hua Ma、Fan-Xiao Meng、Bao-Li Chen、Shao-Liang Zhang、Qian-Li Li、Shu-Wen Gong、Da-Qi Wang、Chun-Lin Ma
DOI:10.1021/acs.orglett.8b01862
日期:2018.7.20
A versatile Lewis acid catalyzed tandem cyclization of in situgenerated alkynyl o-quinone methides (o-AQMs) with electron-rich phenols has been developed on the basis of the mode involving an intermolecular 1,4-conjugate addition/6-endo cyclization/1,3-aryl shift/intramolecular 1,4-conjugate addition cascade. This reaction provides a new method for expeditious assembly of synthetically and biologically
Enantioselective Addition of Thiols to ortho-Quinone Methides Catalyzed by Chiral Phosphoric Acids
作者:Jianwei Sun、Zengwei Lai
DOI:10.1055/s-0035-1560546
日期:——
The first Bronsted acidcatalyzed enantioselective addition of thiols to the in situ generated ortho-quinone methides (o-QMs) is described. Complementary to the chiral amine catalyzed approach, the present reaction employs a chiral phosphoric acid as the catalyst. The readily available o-hydroxybenzyl alcohols serve as the atom-economical precursors of o-QMs to react with tritylthiol with moderate
Copper-Catalyzed Dehydrative Cyclization of 1-(2-Hydroxyphenyl)propargyl Alcohols with P(O)H Compounds for the Synthesis of 2-Phosphorylmethylbenzofurans
A tetrakis(acetonitrile)copper(I) hexafluorophosphate [Cu(MeCN)PF6]‐catalyzed dehydrative reaction of 1‐(2‐hydroxyphenyl)propargyl alcohols with diarylphosphine oxides has been developed to provide an efficient synthesis of phosphorylated benzofurans in good to high yields. In the presence of a catalytic amount of an organic base, a variety of H‐phosphonates and H‐phosphinates can also be employed
A convergent and highly stereoselective [4+2] cycloaddition of in situ‐generated ortho‐Quinone methides (o‐QMs) and azlactone enols has been successfully developed through a triple Brønsted acid catalysis strategy. This protocol provides an efficient and mild access to various densely functionalized dihydrocoumarins bearing adjacent quaternary and tertiary stereogenic centers in high yields with excellent
B(C<sub>6</sub>F<sub>5</sub>)<sub>3</sub>-Catalyzed formal (4+1)-annulation of <i>ortho</i>-quinone methides with diazoacetates: access to 2,3-dihydrobenzofurans
作者:Guangyang Xu、Shengbiao Tang、Ying Shao、Jiangtao Sun
DOI:10.1039/c9cc04863d
日期:——
A novel B(C6F5)3-catalyzed formal (4+1)-cycloaddition reaction of alkyne-tethered ortho-quinone methides with diazoacetates has been well established.