Bacterial Biotransformation of Isoprene and Related Dienes
作者:Derek R. Boyd、David Clarke、Marcel C. Cleij、John T. G Hamilton、Gary N. Sheldrake
DOI:10.1007/s007060070096
日期:2000.6.15
Pseudomonas putida ML 2 was used in the oxidative biodegradation of the acyclic dienes isoprene, trans -piperylene, cis -piperylene, and 1,3-butadiene. Regioselective dioxygenase-catalyzed dihydroxylation of alkenes yielded vicinal diols in the preferred sequence monosubstituted > cis -disubstituted > gem -disubstituted > trans -disubstituted. The isolated diol metabolites had an excess of the R
细菌 恶臭假单胞菌 在无环二烯烃的氧化降解,使用ML 2异戊二烯, 反式 -piperylene, 顺 -piperylene,和1,3-丁二烯。区域选择性双加氧酶催化的烯烃的二羟基化产生邻位二醇,优选的顺序为单取代> 顺式- 二取代> 宝石- 二取代> 反式- 二取代。分离出的二醇代谢物具有过量的 R 构型(9–97% ee ),并通过加入丙二醇作为抑制剂来控制进一步的二醇氧化。使用ML2菌株的立体选择性是由于酶的不对称烯烃二羟基化和二醇的动力学拆分而产生的。 R 构型的烯丙基仲醇基团的对映选择性氧化产生相应的不饱和酮醇 。回收的残留二醇的 S 构型大大过量(≥93% ee ) 。除了产生不饱和二醇和酮醇的酶二烯氧化步骤之外,还发现了酶烯加氢产生饱和酮醇和二醇的证据。
.alpha.,.beta.-Unsaturated Acetals as Precursors of .alpha.-Substituted Ethoxy Dienes. Useful Reagents for Nucleophilic Acylation
作者:Cristina Prandi、Paolo Venturello
DOI:10.1021/jo00097a059
日期:1994.9
The reaction of (E)-1,1-diethoxybut-2-ene (1a) and 1,1-diethoxy-3-methylbut-2-ene (1b) with 2 equiv of sec-butyllithium complexed with potassium tert-butoxide (Schlosser's base) in THF at -95 degrees C gives 1-metalated 1-ethoxy 1,3-dienes that are synthetically equivalent to acyl anions. Subsequent reaction with suitable electrophiles, such as alkyl halides, aldehydes, ketones, carbon dioxide, and carboxylic acid derivatives, affords (E)-1-substituted 1-ethoxy 1,3-dienes 2a-i. Experimental procedures are given for the reaction of the carbanionic intermediates with the electrophiles. Some typical examples for the conversion of the produced alpha-substituted alkoxy dienes into the corresponding alpha,beta-unsaturated carbonyl compounds are also reported. In particular, in the case in which crotonaldehyde is used as an electrophile, the addition product 2c undergoes acid-catalyzed conversion to compounds 4c, 5c, and 6c as a function of the experimental conditions.
Prandi Cristina, Venturello Paolo, J. Org. Chem., 59 (1994) N 18, S 5458-5462
作者:Prandi Cristina, Venturello Paolo
DOI:——
日期:——
Ligand-Controlled Rhodium-Catalyzed Site-Selective Asymmetric Addition of Arylboronic Acids to α,β-Unsaturated Cyclic <i>N</i>-Sulfonyl Ketimines
作者:Chun-Yan Wu、Yu-Fang Zhang、Ming-Hua Xu
DOI:10.1021/acs.orglett.8b00289
日期:2018.4.6
rhodium-catalyzed asymmetric 1,4-/1,2-addition of arylboronic acids to challenging α,β-unsaturatedcyclic ketimines was realized through a ligand-controlled strategy. By employing different chiral olefin ligands, a ligand-controlled switch in the reaction regioselectivity was attained for the first time. The reactions allow the synthesis of highly valuable α,α-disubstituted chiral allylic amines and enantioenriched