设计并合成了以D和O为中心的以D为中心的自由基阳离子Oxo + O •和Oxo + C •的新型前体,它代表了聚酯降解过程中产生的自由基的模型系统。前体配备有硝酸盐官能团,该官能团充当这些烷氧基和碳自由基的掩蔽位点,这些烷氧基和碳自由基通过碰撞诱导解离(CID)释放出来。Oxo + O •和Oxo + C •具有循环碳氧离子作为永久电荷标签,从而可以在质谱仪的离子阱中在毫秒到秒的时间内监控它们的离子-分子反应。Oxo +的反应通过产品和动力学研究,对具有环己烯,环己二烯,乙酸乙酯,1,1-二甲氧基乙烷和1,2-二甲氧基乙烷的O •和Oxo + C •均表现出完整和不良聚酯均具有的结构特征进行了研究,以鉴定“ “热点”是指自由基引起的聚酯损伤。所有与Oxo + O •的反应都非常快,并且主要通过HAT进行。在我们的实验时间范围内,Oxo + C •的反应性降低了大约两个数量级,并且没有通过氢
A One-Pot Reaction of α-Imino Rhodium Carbenoids and Halohydrins: Access to 2,6-Substituted Dihydro-2<i>H</i>-1,4-oxazines
作者:Kieran D. Jones、Michael J. Nutt、Elena Comninos、Alexandre N. Sobolev、Stephen A. Moggach、Tomoya Miura、Masahiro Murakami、Scott G. Stewart
DOI:10.1021/acs.orglett.0c00947
日期:2020.5.1
a Rh(II)-catalyzed reaction between 1-tosyl-1,2,3-triazoles and halohydrins to provide 2,6-substituted 3,4-dihydro-2H-1,4-oxazines under basic conditions. The reaction is proposed to undergo a rhodiumcarbenoid 1,3-insertion into O-H followed by an annulation. The scope includes phenyl or alkenyl C4-substituted triazoles and a range of halohydrins using catalytic Rh2Oct4 and K2CO3. A synthesis of the
An Efficient Method for the Chemoselective Preparation of Benzoylated 1,2-Diols from Epoxides
作者:A. Khalafi-Nezhad、M. N. Soltani Rad、A. Khoshnood
DOI:10.1055/s-2003-42416
日期:——
A very efficient and highly regioselective ring-opening reaction of epoxides with benzoic acid and its derivatives in the presence of cat. amount of tetrabutylammonium bromide (TBAB) in anhydrous acetonitrile has been developed. This effective method is useful for the preparation of selectively protected diols as precursor for many organic syntheses such as those of acyclic nucleosides and other synthetic
The reaction of epoxides with lithiumhalides was efficiently promoted on the surface of silica gel in the absence of any solvent to give the corresponding β-halohydrins. The reactivity of lithiumhalides was shown to follow the order LiI> LiBr>> LiCl, and the reactivity of LiCl was dramatically increased by adding an equivalent amount of water to this system. On the other hand, a similar reaction
Synthesis of some halogenated and disubstituted amino benzylacyclouridine derivatives
作者:Bai-Chuan Pan、Zhi-Hao Chen、Elizabeth C. Rowe、Shih-Hsi Chu
DOI:10.1002/jhet.5570290402
日期:1992.7
1′-Halogenomethyl, 1′-azidomethyl and 1′-disubstituted aminomethyl derivatives of BAU (5-benzylacyclouridine) and BBAU (5-benzyloxybenzylacyclouridine) were synthesized in the course of our studies of benzylacyclouridines. Two new and more convenient preparations of the previously known aminomethyl-and hydroxymethyl-parent compounds of these two series, AM-BAU, AM-BBAU and HM-BBAU are also reported
Regioselective and stereospecific opening of an oxirane system mediated by trifluoroacetic acid and halide anions. A new direct approach to C3-vicinal halohydrins
作者:Stephan D. Stamatov、Jacek Stawinski
DOI:10.1016/j.tetlet.2007.01.083
日期:2007.3
derivatives bearing ester, ether or silyl functionality upon treatment with trifluoroacetic acid (TFA) in the presence of a halide anion (e.g., Bu4NX; X = Cl, Br or I) at room temperature undergo regioselective and stereospecific opening of the oxiranering to produce the corresponding C3-vicinal haloalkanols in practically quantitative yields.
在室温下,在卤化物阴离子(例如,Bu 4 NX; X = Cl,Br或I)存在下,用三氟乙酸(TFA)处理后,带有酯,醚或甲硅烷基官能团的缩水甘油衍生物经历环氧乙烷的区域选择性和立体选择性开放环以实际定量的产率生产相应的C3-邻位卤代链烷醇。