Experimental and Theoretical Study of the 2-Alkoxyethylidene Rearrangement
作者:Kimberly S. Graves、Dasan M. Thamattoor、Paul R. Rablen
DOI:10.1021/jo1020536
日期:2011.3.18
The rearrangement of 2-ethoxyethylidene, generated photochemically from a nonnitrogenous precursor, leads to ethyl vinyl ether. Although this product could result, in principle, from a 1,2-hydrogen shift and/or a 1,2-ethoxy shift in the carbene, a deuterium labeling study indicates an essentially exclusive preference for hydrogen migration. The experimental results are in agreement with CCSD and W1BD
Photochemistry of 1-(propan-2-ylidene)-1a,9b-dihydro-1H-cyclopropa[l]phenanthrene
作者:Tarini S. Hardikar、MacKenzie A. Warren、Dasan M. Thamattoor
DOI:10.1016/j.tetlet.2015.10.064
日期:2015.12
enanthrene, affords dimethylvinylidene upon photolysis (∼315–400 nm) at ambient temperature, and the carbene may be trapped by cyclohexene. Some of the precursor also rearranged to a non-photolabile isomer via a putative 1,5-sigmatropic shift followed by an electrocyclicringopening.
碳氢化合物1-(丙烷-2-亚烷基)-1a,9b-二氢-1 H-环丙烷[ l ]菲在环境温度下(〜315-400 nm)光解时提供二甲基亚乙烯基,卡宾可能被碳环己烯。某些前体还通过推定的1,5-σ移位和随后的电环开环重新排列为非光不稳定异构体。
A Simple Synthesis of 1,1-Dibromo-1a,9b-dihydrocyclopropa<b>[</b>
<b><i>l</i></b>
<b>]</b>phenanthrene<b />
作者:Dasan Thamattoor、Jennifer Nguyen
DOI:10.1055/s-2007-983763
日期:——
An improved procedure for preparing the title compound, resulting in substantially higher yields under simpler conditions, is described.
描述了制备标题化合物的改进程序,在更简单的条件下产生显着更高的产率。
Formation and Rearrangement of a Congested Spiropentane from the Trapping of Dibenzonorcarynyliden(e/oid) by Phencyclone
作者:Alexander D. Roth、Dasan M. Thamattoor
DOI:10.1021/acs.orglett.4c01001
日期:2024.5.10
low-temperature treatment of 1,1-dibromo-1a,9b-cyclopropa[l]phenanthrene with butyllithium appeared to produce dibenzonorcarynyliden(e/oid) which could be intercepted with phencyclone to produce a hindered spiropentane. The spiropentane readily rearranges, thermally and photochemically, into a triphenylene phenol derivative. The spiropentane and its rearrangement product were characterized by X-ray crystallography
用丁基锂低温处理 1,1-二溴-1a,9b-环丙[ l ]菲似乎会产生二苯并正亚芳基 (e/oid),它可以被苯环酮拦截,产生受阻螺戊烷。螺戊烷很容易通过热和光化学重排成苯并菲苯酚衍生物。通过X射线晶体学对螺戊烷及其重排产物进行了表征。
Experimental and Theoretical Investigations of Ring-Expansion in 1-Methylcyclopropylcarbene
作者:Dasan M. Thamattoor、John R. Snoonian、Horst M. Sulzbach、Christopher M. Hadad
DOI:10.1021/jo9903454
日期:1999.8.1
1-Methylcyclopropylcarbene, generated by photolysis of two isomeric hydrocarbon precursors, undergoes ring-expansion readily to give 1-methylcyclobutene. Experimentally, intramolecular carbon-hydrogen insertions are not observed. Trapping studies with TME demonstrates the formation of the expected cyclopropane adduct, and via a double-reciprocal analysis, the lifetime of 1-methylcyclopropylcarbene was determined to be 12 ns in 1,1,2-trichlorotrifluoroethane. Computational studies show that the barrier to ring-expansion is significantly smaller in 1-methylcyclopropylcarbene than in cyclopropylcarbene. The origin of the increased rate of ring-expansion is due to stabilization of the positive charge that occurs at the incipient tertiary carbon that is attached to the migrating carbon center.