The importance of cyclopentanoid natural products continues to inspire the development of methods for the synthesis of 5-membered rings. For example, the Conia–ene reaction provides an atomeconomical synthesis of methylenecyclopentanes by the thermal cyclization of e-acetylenic carbonyl compounds. While the classic thermal reaction is limited to the exocyclic cyclization mode, group 6 metal com...

An improved synthesis of bicyclo[2.2.1]hept-5-ene-2,3-dione by Swern oxidation of bicyclo[2.2.1]hept-5-ene-2,3-diol, and an unexpected ring-opening reaction by the Swern oxidation of pyrazine-fused congeners are described.

Air-sensitive and air-stable primary phosphines (RPH2) were compared for their ability to undergo photoinitiated phosphane-ene chemistry with 1-hexene. Despite their increased air-stability, the primary phosphines displayed equal to or greater reactivity when compared to air-sensitive alkyl or aryl analogues. The phosphane-ene reaction was also performed in the presence of 1-octanethiol to dete...

The hydrophosphination reaction of 1,3-butadiene in the presence of Cp(2)EuH has been studied by DFT methods. It has been possible to show that such a reaction can be catalytically performed and that the active species is Cp(2)EuPH(2). The phosphido complex can be formed from the hydride either in a one step reaction (direct P-H activation in the presence of Cp(2)EuH) or in a two-step reaction ...

The geometry of the double bond in oxazolidinone-substituted ene carbamates controls the mode selectivity (ene reaction versus [2+2] cycloaddition) of singlet oxygen through stereoelectronic effects, whereas the chiral auxiliary provides high diastereoselectivity through steric shielding.

ABSTRACT The Diels-Alder reaction between methyl (Z)-2-nitro-3-(4-nitrophenyl)-2-propenoate and cyclopentadiene yields a mixture of carbodiene Diels-Alder adducts. B3LYP/6-31G(d) simulations indicate that the conversion of addends into methyl (1R*,2S*,3S*,4R*)-2-nitro-3-(4-nitrophenyl)-bicyclo[2.2.1]hept-5-ene-2-carboxylate occurs via two-stage heterodiene Diels-Alder reaction and (in a second ...

3,5-disubstituted-2,6-dicyanoaniline derivatives have been synthesized via the reaction of aryl methylene- and 1-arylethylidenemalonodinitriles using 1,8-diazabicyclo[5.4.0] undec-7-ene (dbu) as a  novel and highly efficient catalyst under conventional as well as microwave conditions. use of non-hazardous, inexpensive and readily available base catalyst, convenient procedure, short reaction tim...

The removal of SO2 in the presence of alkene-ozone systems has been studied for ethene, cis-but-2-ene, trans-but-2-ene and 2,3-dimethyl-but-2-ene, as a function of humidity, under atmospheric boundary layer conditions. The SO2 removal displays a clear dependence on relative humidity for all four alkene-ozone systems confirming a significant reaction for stabilised Criegee intermediates (SCI) wi...