Stereospecific Synthesis of Polysubstituted <i>E</i>-Olefins by Reaction of Acyclic Nitrones with Free and Platinum(II) Coordinated Organonitriles
作者:Jamal Lasri、M. Adília Januário Charmier、Matti Haukka、Armando J. L. Pombeiro
DOI:10.1021/jo061659b
日期:2007.2.1
Free nitriles NCCH2R (1a R = CO2Me, 1b R = SO2Ph, and 1c R = COPh) with an acidic α-methylene react with acyclic nitrones -O+N(Me)C(H)R‘ (2a R‘ = 4-MeC6H4 and 2b R‘ = 2,4,6-Me3C6H2), in refluxing CH2Cl2, to afford stereoselectively the E-olefins (NC)(R)CC(H)R‘ (3a−3c and 3a‘−3c‘), whereas, when coordinated at the platinum(II) trans-[PtCl2(NCCH2R)2] complexes (4a R = CO2Me and 4b R = Cl), they undergo
自由腈NCCH 2 R(1A R = CO 2 Me中,1B R = SO 2 Ph和1C与酸性R = COPH)α亚甲基与无环硝酮反应- ø + N(Me)的C(H)R”(2a R'= 4-MeC 6 H 4和2b R'= 2,4,6-Me 3 C 6 H 2),在回流的CH 2 Cl 2中,以立体选择性地得到E-烯烃(NC)(R)C C(H)R'(3a - 3c和3a '− 3c '),而当与铂(II)的反式-[PtCl 2(NCCH 2 R)2 ]配合物(4a R = CO 2 Me和4b R = Cl)配位时,它们进行环加成反应生成(恶二唑啉) )-Pt II络合物(R = CO 2 Me中,Cl和R” = 4-MEC 6 ħ 4,2,4,6-ME 3 c ^ 6 ħ 2)(图5A-5D)。在CH 2 Cl 2中加热后,5a得到相应的烯烃3a。当在聚焦微波辐射下,特别是在没有溶剂的固相(SiO