Synthesis of methacrylic-type peroxidic compounds and study of their homolytic induced decomposition in solution
作者:Daniel Colombani
DOI:10.1016/s0040-4020(96)01180-5
日期:1997.2
unsaturated peroxidic compounds have been prepared, characterized and inductively decomposed in various solvents to afford the corresponding oxiranes. The reaction proceeded by a radical chain mechanism and was initiated either by thermolysis of added t-butyl peracetate at 110°C or AIBN at 80°C, or by autoxidation of BEt3 at 20°C. The studied peroxyderivatives were designed to generate oxyl radicals reacting
Alpha carbocation stabilization by silicon, germanium and tin
作者:John A. Soderquist、Alfred Hassner
DOI:10.1016/s0040-4039(00)82072-9
日期:1988.1
The hydrolyses of a number of α-metalloidal vinyl ethers were found to undergo a rate-limiting protonation to produce α- silyl, germyl or stannyl carbocations. Comparative rate data leads to the ordering: C>Sn>Ge>Si>H, for the stabilization of such intermediates.
Spectroscopy of the acetyl anion CH3CO- and radical CH3CO
作者:Mark R. Nimlos、J. A. Soderquist、G. Barney Ellison
DOI:10.1021/ja00202a001
日期:1989.9
minus}1}, nu}sub 11}(CHsub 2}DCO) = 500 plus minus} 50 cmsup minus}1}, and nu}sub 11}(CHsub3}COsup minus}}) = 570 plus minus} 180 cmsup minus}1}. From a Franck-Condon analysis of the vibronic peak intensities we have estimated these C-C-O bond angles for the acetyl anion and radical: alpha}(CCO)(CHsub3}COsup minus}}) = 110 plus minus} 5degree} and alpha}(CCO)(CHsub3}CO) = 133 plus
Stereoselective synthesis of β- C - d -glucopyranosides using the reaction of TMSCN and Grignard reagents with cyclic five-membered sulfonium salt intermediates
作者:Hui Liu、Irina P Smoliakova
DOI:10.1016/s0040-4020(01)00160-0
日期:2001.4
the presence of a Lewis acid, ArSCl adducts of tri-O-benzyl-d-glucal react with vinyl ethers to form cyclic five-membered sulfonium salt intermediates. The latter are capable of reacting with TMSCN and Grignardreagents furnishing exclusively 2-S-(aryl)-2-thio-β-C-d-glucopyranosides. The one-pot reaction also proceeds with high stereoselectivity of C–C bond formation in the lateral chain providing exclusively
在路易斯酸的存在下,三-O-苄基-d-葡糖醛的ArSCl加合物与乙烯基醚反应形成环状五元sulf盐中间体。后者能够与TMSCN和仅提供2- S-(芳基)-2-硫代-β- C -d-吡喃葡萄糖苷的格利雅试剂反应。一锅法反应还会在侧链中形成C–C键的立体选择性高的情况下进行,从而仅或主要提供具有侧链中手性中心的(S)-构型的C-糖苷。
Reaction of vinyl ethers with ArSCl adducts of d-glucal
作者:Irina P. Smoliakova、Mingming Han、Jianchun Gong、Ron Caple、William A. Smit
DOI:10.1016/s0040-4020(99)00161-1
日期:1999.4
Lewis acid mediated reactions of vinylethers with ArSCl adducts of benzyl protected D-glucal followed by quenching of the five-membered sulfonium salt intermediates with external nucleophiles, H2O, MeOH, and n-Bu4NBH4, lead to a highly stereoselective formation of β-C-glucopyranosides with different functional groups in the lateral chain.
路易斯酸介导的乙烯基醚与苄基保护的D-葡糖的ArSCl加合物的反应,然后用外部亲核试剂,H 2 O,MeOH和n- Bu 4 NBH 4淬灭五元sulf盐中间体,从而产生高度立体选择性的形成β - ç -葡糖吡喃糖苷在横向链不同的官能团。