these three t-butyl peresters are similar to each other may indicate the absence of the ionic character in the transition state suggesting the almost complete homolytic decomposition of these peresters. Although the typical concerted decomposition might be invalid for these peresters in view of the activation parameters, it would be suggested from the product studies that the decomposition of these peresters
每(反式-2-取代的环丙基)乙酸酯的三种叔丁基酯(RH,CH 3,C 6 H 5)由相应的酰氯合成,然后在环己烷中热分解,以研究环丙基羰基的化学稳定性和行为。在所有的热分解反应中均获得了干净的一级动力学。这三种叔丁基过酸酯的分解速率和活化参数彼此相似的实验事实可能表明,在过渡态下没有离子特性,表明这些酯几乎完全被同质分解。尽管考虑到激活参数,典型的一致分解对于这些peresters可能是无效的,从产物研究中可以看出,这些过酸酯的分解特征是在它们的O = O键裂变时它们的酰基-烷基键大量损失。叔丁基每(在各种供氢溶剂中的乙酸反( -2-苯基环丙基)乙酸酯由三种烃和两种叔丁基醚组成。这些叔丁基醚,可能是笼状产物的形成是重要的。
Radical Reaction Initiated and Stereocontrolled by Zinc Chloride
The reaction of allyltributyltin with methyl 2-[N-((4S)-4-(1-methylethyl)-2-oxazolidinone-3-carbamoyl)amino]-2-bromoacetate (5a) was accelerated at -50 degrees C in the presence of AIBN and stopped in the presence of galvinoxyl, indicating that the reaction proceeds through a radical mechanism. The reaction was accelerated dramatically at -78 degrees C in the presence of ZnCl2 . OEt2, and the ZnCl2-mediated reaction was stopped in the presence of galvinoxyl. In the presence of 2 equiv ZnCl2 . OEt2, the reaction afforded methyl (2R)-2-[N-((4S)-4-(1-methylethyl)-2-oxazolidinone-3- carbamoyl)amino]4-pentenoate 6a(R)} with high diastereoselectivity (93:7). Taken together, ZnCl2 . OEt2 works as a radical initiator as well as chelating agent.
Facile Direct Coupling Reactions of
<scp>MOM</scp>
‐protected Benzylic Alcohols Using Aluminum Chloride
作者:Tien Tan Bui、Hee‐Kwon Kim
DOI:10.1002/bkcs.12358
日期:2021.9
used protecting groups for alcohols. This study describes novel direct functionalization of the MOM-protected benzylic alcohols. Preparation of allylic compounds from benzyl MOM ethers was successfully achieved by utilization of allyltrimethylsilane and AlCl3. In addition, direct azidation of benzyl MOM ethers using TMSN3 was successful carried out under AlCl3-mediated reaction conditions. These results