Cyclopentadienones via a Tandem
<i>C</i>
‐Cyclopropylnitrone Cyclization‐Cycloreversion Sequence
作者:Ihsan Erden、Christian Gärtner、Jingxiang Ma、Gabriel Cabrera、Kate Markham、Saeed Azimi、Scott Gronert
DOI:10.1002/ejoc.201700915
日期:2017.9.15
from spiro[2.4]hepta-4,6-diene-1-carbaldehyde and its benzo analog undergo a tandem uncatalyzed intramolecular cyclopropane-nitrone cyclization-5,6-dihydro-1,2-oxazine cycloreversion to give cyclopentadienones. Similarly, the NH-nitrone generated in situ from spiro[cyclopropane-1,1'-indene]carbaldehyde oxime leads to benzocyclopentadienone (1H-inden-1-one) by the same mechanism. DFT calculations are
源自螺[2.4]庚-4,6-二烯-1-甲醛及其苯并类似物的醛硝酮经历串联的未催化分子内环丙烷-硝酮环化-5,6-二氢-1,2-恶嗪环化反应,得到环戊二烯酮。类似地,由螺[环丙烷-1,1'-茚]甲醛肟原位生成的NH-硝酮通过相同的机制生成苯并环戊二烯酮(1H-inden-1-one)。DFT 计算有利于环化的协调但高度异步的途径。使用二氢和四氢衍生物进行的对照实验表明,螺环戊二烯单元对于反应的成功至关重要,从而引发了螺共轭效应以增加环丙烷的反应性。