Reactions of in situ formed acyl tributylphosphonium ions with Grignard reagents as an effective route to ketones from acid chlorides
作者:Hatsuo Maeda、Junko Okamoto、Hidenobu Ohmori
DOI:10.1016/0040-4039(96)01083-0
日期:1996.7
The reactions of acyl tributylphosphonium ions in situ generated from acid chlorides and Bu3P in THF at −22°C with primary alkyl and arylmagnesium halides have proved to be a convenient and simple procedure to prepare ketones from acid chloride in one-pot.
Efficient Stereoselective Synthesis of Structurally Diverse γ‐ and δ‐Lactones Using an Engineered Carbonyl Reductase
作者:Meng Chen、Xiao‐Yan Zhang、Chen‐Guang Xing、Chao Zhang、Yu‐Cong Zheng、Jiang Pan、Jian‐He Xu、Yun‐Peng Bai
DOI:10.1002/cctc.201900382
日期:2019.6.6
efficiently synthesized stereoselectively using an engineered carbonyl reductase from Serratia marcescens (SmCRV4). SmCRV4 exhibited improved activity (up to 500‐fold) and thermostability toward 14 γ‐/δ‐keto acids and esters, compared with the wild‐type enzyme, with 110‐fold enhancement in catalytic efficiency (kcat/Km) toward methyl 4‐oxodecanoate. The preparative synthesis of alkyl and aromatic γ‐ and δ‐lactones
结构结构多样的γ-和δ-内酯是利用粘质沙雷氏菌(Sm CR V4)中的一种工程化羰基还原酶有效地立体选择性合成的。与野生型酶相比,Sm CR V4表现出更高的活性(最高达500倍)和对14种γ-/δ-酮酸和酯的热稳定性,催化效率提高了110倍(k cat / K m)对4-氧代十二烷甲酸甲酯。证明了烷基和芳香族γ-和δ-内酯的制备合成,其ee率为95%-> 99%,收率为78%-90%。最高时空产量为1175 g L -1 d -1,达到了(R)-γ-癸内酯
Synthesis of unstrained Criegee intermediates: inverse α-effect and other protective stereoelectronic forces can stop Baeyer–Villiger rearrangement of γ-hydroperoxy-γ-peroxylactones
作者:Vera A. Vil'、Yana A. Barsegyan、Leah Kuhn、Maria V. Ekimova、Egor A. Semenov、Alexander A. Korlyukov、Alexander O. Terent'ev、Igor V. Alabugin
DOI:10.1039/d0sc01025a
日期:——
by exploring the interplay between the primary and secondary stereoelectronic effects in the Baeyer–Villiger (BV) rearrangement by experimental and computationalstudies of γ-OR-substituted γ-peroxylactones, the previously elusive non-strained Criegee intermediates (CI). These new cyclic peroxides were synthesized by the peroxidation of γ-ketoesters followed by in situ cyclization using a BF3·Et2O/H2O2
在从不稳定的中间体中消除立体声电子保护时,我们可以将限制推到多远?我们通过对γ-OR取代的γ-过氧内酯(以前难以捉摸的Criegee中间体(CI))进行实验和计算研究,探索了Baeyer-Villiger(BV)重排中主要和次要立体电子效应之间的相互作用,从而解决了这个问题。 。这些新的环状过氧化物是通过γ-酮酸酯的过氧化反应,然后使用BF 3 ·Et 2 O / H 2 O 2系统原位环化而合成的。尽管主要影响(迁移的C–R m的排列带有断裂的O–O键的碳键在6元环中具有活性,次级作用的减弱(从OR孤对到断裂的C–R m键的捐赠)提供了足够的动力学稳定性,从而允许形成和分离稳定的γ-氢过氧-γ-过氧内酯,在C6-位带有甲基取代基。此外,源于两个新的立体电子因素的反应物稳定化也提供了补充保护,这两个因素在本工作中首次被确定和量化。首先,对γ-氢过氧-γ-过氧内酯的意料之外的偏爱削弱了主要的立体电子效应,并引入了约2
Reactions of Grignard Reagents with Bis- or Mono-Phosphonium lons in Situ Generated from Bu3P and Dicarboxylic Acid Dichlorides or .OMEGA.-Ethoxycarbonyl Alkanoyl Chlorides as a Novel Method to Obtain Diketones and Ketoesters.
mixture of BusP and the Grignard reagent (2.0 eq each) was added to the dichloride solution at the same temperature, a better result was obtained. The latter method not with PhMgBr but with n-BuMgCl or MeMgBr was shown to be useful for preparation of symmetrical alkanediones and keto alkanoates from various 5 (n=2-6) and 13 (n=2 or 3), respectively. For synthesis of alpha-diketones or alpha-ketoesters
Synthesis and antimicrobial activity of 5-alkyl-1-(3-oxobutyl)pyrrolidin-2-ones and their 2,4-dinitrophenylhydrazones
作者:A. A. Safonova、V. A. Sedavkina
DOI:10.1007/bf02333889
日期:1996.10
us to obtain 2-pyrrolidones with oxo and cyano groups in the substituent at the nitrogen atom, because the reduction amination process was accompanied by hydrogenation of these functional groups. Introduction of an oxoalkyl substituent at the nitrogen atom of pyrrolidin-2-ones offers the possibility to modify their structures by reactions involving the oxo group, which leads to the synthesis of new