Mechanistic Investigation of Enediyne-Connected Amino Ester Rearrangement. Theoretical Rationale for the Exclusive Preference for 1,6- or 1,5-Hydrogen Atom Transfer Depending on the Substrate. A Potential Route to Chiral Naphthoazepines
作者:Damien Campolo、Anouk Gaudel-Siri、Shovan Mondal、Didier Siri、Eric Besson、Nicolas Vanthuyne、Malek Nechab、Michèle P. Bertrand
DOI:10.1021/jo202580y
日期:2012.3.16
used to demonstrate that the cascade rearrangement of enediyne-connected amino esters 1a and 1b evolved through exclusive 1,5- or 1,6-hydrogen atom transfer, subsequent to 1,3-proton shift and Saito–Myers cyclization, depending on the structure of the starting material. These results were independently confirmed by DFT theoretical calculations performed on model monoradicals. These calculations clearly
手性记忆(MOC)和氘标记研究用于证明烯二炔连接的氨基酯1a和1b的级联重排是通过排他的1,5-或1,6-氢原子转移形成的,随后是1,3-质子转移和Saito–Myers环化,取决于起始材料的结构。这些结果通过对模型单基进行的DFT理论计算独立确认。这些计算清楚地表明,在丙氨酸系列中,由于1,5-氢的移动较之1,6-氢的移动更具有动力学上的优势,因此在动力学上比1,6-氢的移动更受青睐。在缬氨酸系列中,氮原子上的大部分取代基对反应的命运有重大影响。ñ-甲苯磺酸化增加了1,5-氢转移的屏障,从而有利于1,6-氢转移。探索了1,6-氢原子转移的现成可用性,作为对映体合成萘并氮杂的潜在途径。