85696-84-0Relevant articles and documents
Developing the Saegusa-Ito Cyclisation for the Synthesis of Difluorinated Cyclohexenones
Percy, Jonathan M.,McCarter, Adam W.,Sewell, Alan L.,Sloan, Nikki,Kennedy, Alan R.,Hirst, David J.
supporting information, p. 19119 - 19127 (2016/01/26)
Palladium(II)-catalysed cycloalkenylation (Saegusa-Ito cyclisation) has been used for the first time to transform difluorinated silylenol ethers to difluorinated cycloalkenones under mild conditions. The silylenol ether precursors were prepared in two high-yielding steps from trifluoroethanol, and cyclised in moderate to good yields. A combination of air and copper(I) chloride in acetonitrile gave the turnover of the initial palladium(II) salt, whereas the provision of an oxygen atmosphere ensured more rapid reaction. Annulations required a minimum level of substitution on the chain, but failed when the alkene was substituted. Annelations allowed a range of n,6-bicyclic systems to be prepared and afforded three products, in which heterocycles were fused to the new cyclohexenone. The least substituted system explored underwent cyclisation followed by terminal oxidation to a cyclic enal, which corresponded to a Wacker product of unusual regiochemistry.
Toward the total synthesis of palhinine A: Expedient assembly of multifunctionalized isotwistane ring system with contiguous quaternary stereocenters
Zhang, Guo-Biao,Wang, Fang-Xin,Du, Ji-Yuan,Qu, Hu,Ma, Xiao-Yan,Wei, Meng-Xue,Wang, Cheng-Tao,Li, Qiong,Fan, Chun-An
supporting information; experimental part, p. 3696 - 3699 (2012/09/21)
The stereoselective, expedient assembly of the key functionalized isotwistane (bridged tricyclo[4.3.1.03,7]decane) system, 5/6/6 ring, with contiguous quaternary stereocenters in Lycopodium alkaloid palhinine A and its analogues via an intramol
Reaction of Phosphonate-Stabilized Carbanions with Cyclic Enones Bearing a β-Leaving Group
Mphahlele, Malose J.,Modro, Tomasz A.
, p. 8236 - 8240 (2007/10/03)
Reaction between α-lithiated alkylphosphonic esters and α,β-unsaturated cyclopentenones and cyclohexenones carrying a heteroatom substituent Y in the β-position was studied.Complete chemoselectivity was observed as a function of substituent Y.For Y = OMe exclusive addition-elimination at the β-carbon was observed, yielding α,β-unsaturated δ-ketophosphonates.The β-chloro-substituted substrates (Y = Cl) derived from cyclohexenone reacted exclusively at the carbonyl carbon, yielding (2-hydroxyalkyl)phosphonates with the retained chlorovinyl function.The alcohols, depending on the conditions, could be dehydrated to two different products.The reaction of 3-chlorocyclopent-2-en-1-one with diethyl (lithiomethyl)phosphonate occured at the β-carbon, but the ketophosphonate product was isolated in a stable enolic form.
