Barriers to intramolecular hydride transfers in some polycyclic hydroxyketones
作者:Gabrielle-Anne Craze、Ian Watt
DOI:10.1039/p29810000175
日期:——
The hydroxyketones (1) and (2) have been prepared from the Diels–Alder adducts of p-benzoquinone with cyclopentadiene and cyclohexa-1,3-diene. The boron trifluoride–ether catalysed reaction of cyclohepta-1,3-diene with p-benzoquinone gave good yields of the Diels–Alder adduct which was converted into hydroxyketone (3). Experiments with cyclohexanol and admantan-2-ol established characteristic 13C n
羟基酮(1)和(2)是由对苯醌与环戊二烯和环己-1,3-二烯的Diels-Alder加合物制备的。三氟化硼-醚催化的环庚-1,3-二烯与对-苯醌的反应产生了良好的Diels-Alder加合物收率,该加成物转化为羟基酮(3)。用环己醇和金刚烷-2-醇进行的实验建立了特征性的13 C nmr化学位移,该化学位移与二甲基亚砜中的二甲基钠使醇去质子化有关。制备了(1)-(3)的钠盐溶液,动态13 C nmr光谱为其> 21.7(100°C),19.0(100°C)和17.3(72°C)的简并重排提供了障碍大卡摩尔–1, 分别。借助经验力场计算,讨论了势垒变化与分子几何形状之间的关系。
Topologically driven tandem radical cyclization-based strategy for the synthesis of oxa- and aza-cages
作者:Santosh J. Gharpure、Suheel K. Porwal
DOI:10.1016/j.tetlet.2009.10.024
日期:2009.12
Tandem radical cyclization-based strategy for the synthesis of oxa- and aza-cage compounds is described. The aryl iodides 1 and N-tosyl propargylated amine 8 lead to oxa- and aza-cages, respectively, after two tandem 5-exo-trig radicalcyclizations. The alcohols 11 on reaction with nBu3SnH and AIBN give rise to the oxa-cages 14 bearing the tributyltin moiety after three tandem 5-exo-trig cyclizations
描述了基于串联自由基环化的合成氧杂和氮杂笼化合物的策略。在两次串联的5 -exo-trig自由基环化反应之后,芳基碘化物1和N-甲苯磺酰基炔丙基化的胺8分别导致了oxa-和氮杂-笼。与n Bu 3 SnH和AIBN反应的醇11在三连串的5 -exo-trig环化反应后生成带有三丁基锡部分的氧杂笼14。另一方面,炔丙基醚16在类似条件下的反应通过5 -exo-trig 4来提供氧杂-笼17。-exo-trig,5 -exo-trig串联自由基环化序列。
Stereoselective Synthesis of New Oxa-Cages via Alkyl Radical Cyclization to Vinylogous Carbonates
作者:Santosh Gharpure、Suheel Porwal
DOI:10.1055/s-2007-1000847
日期:2008.1
An efficient strategy is developed for the stereoselectivesynthesis of unsymmetrical dioxa-cage compounds containing ether linkages employing a 6-exo-trig alkyl radicalcyclization to vinylo- gous carbonates. The radical precursors are obtained from the Diels-Alder adducts via iodoetherification and conversion of the al- cohol moiety to vinylogous carbonate. The formation of mono-oxa- cage compounds
Alkyl radical cyclization to vinylogous carbonates for the stereoselective synthesis of unsymmetrical dioxa-cage compounds: effect of conformation on the rate of cyclization versus reduction
作者:Santosh J. Gharpure、Suheel K. Porwal
DOI:10.1016/j.tet.2010.11.098
日期:2011.2
ether linkages employing a 6-exo-trig alkyl radical cyclization to vinylogous carbonates is developed. The radical precursors are prepared from the diols obtained from the Diels–Alder adducts via iodoetherification followed by addition of the alcohol to the ethyl propiolate. The geometrical constrains play important role in deciding the outcome of the reaction as cyclization versus simple reduction
Rapid intramolecular 1,4-hydride transfers in rigid boat-conformation 4-hydroxycyclohexanones
作者:Gabrielle-Anne Craze、Ian Watt
DOI:10.1039/c39800000147
日期:——
The ketols (1a)–(3a), have been prepared and barriers for degenerate rearrangement, by intramolecular hydride transfer, in the derived sodium alkoxides, (1b)–(3b) have been determined from their temperature dependent 13C n.m.r. spectra.
(该酮醇1A) - (3A),已经制备和用于重排退化障碍,通过分子内氢负离子转移,在派生醇钠,(1B) - (3B)已经从它们的温度依赖性测定13 C NMR谱。