114395-16-3Relevant articles and documents
Synthesis of Tetrahydroquinoline-Embedded Bridged Benzothiaoxazepine-1,1-dioxides
Borgohain, Hemi,Devi, Runjun,Dheer, Divya,Borah, Biraj Jyoti,Shankar, Ravi,Das, Sajal Kumar
supporting information, p. 6671 - 6679 (2017/12/07)
A diastereoselective synthesis of previously unknown tetrahydroquinoline-containing bridged benzothiaoxazepine-1,1-dioxides is presented. The three-step protocol uses readily available N-aryl-2-fluorobenzenesulfonamides and trans-2,3-epoxy-cinnamyl-alcohol-derived tosylates as the starting materials, involves N-alkylation of sulfonamides, intramolecular epoxide ring-opening, and SNAr reactions as the reaction steps, and requires only one chromatographic purification to access the desired products in good overall yields.
Scalable, stereoselective syntheses of α,β-difluoro-γ-amino acids
Patel, Alpesh Ramanlal,Hu, Xiang-Guo,Lawer, Aggie,Ahmed, Md. Iqbal,Au, Catherine,Jwad, Rasha,Trinh, Johny,Gonzalez, Christina,Hannah, Elizabeth,Bhadbhade, Mohan M.,Hunter, Luke
, p. 3305 - 3317 (2016/05/19)
Backbone-fluorinated gamma-amino acids are novel shape-controlled building blocks that have potential utility in a variety of biological contexts. However, their synthesis poses challenges in terms of chemo-, regio- and stereoselectivity, and this has proven to be the major bottleneck in the ongoing development of their various biological applications. To address this problem, several new synthetic strategies were investigated in this work. This has led to the identification of new methods that are superior in terms of yield and stereocontrol.
A Tellurium Transposition Route to Allylic Alcohols: Overcoming Some Limitations of the Sharpless-Katsuki Asymmetric Epoxidation
Dittmer, Donald C.,Discordia, Robert P.,Zhang, Yanzhi,Murphy, Christopher K.,Kumar, Archana,et al.
, p. 718 - 731 (2007/10/02)
Good yields of enantiomeric allylic alcohols can be obtained in high enantiomeric excess (ee) by combining Sharpless-Katsuki asymmetric epoxidation process (SAE) with tellurium chemistry.The advantages of the tellurium process are as follows: (1) the 50percent yield limitation on the allylic alcohol in the Sharpless kinetic resolution (SKR) can be overcome; (2) allylic tertiary alcohols which are unsatisfactory substrates in the SKR can be obtained in high optical purity; (3) optically active secondary allylic alcohols with tertiary alkyl substituents (e.g. tert-butyl) at C-1 can be obtained in high ee; (4) optically active sterically congested cis secondary alcohols can be obtained in high ee; and (5) the nuisance of the slow SAE of some vinyl carbinols can be avoided.The key step in the reaction sequence is either a stereospecific 1,3-transposition of double bond and alcohol functionalities or an inversion of the alcohol configuration with concomitant deoxygenation of the epoxide function in epoxy alcohols.Trans secondary allylic alcohols can be converted to cis secondary allylic alcohols by way of erythro epoxy alcohols (glycidols); threo glycidyl derivatives are converted to trans secondary allylic alcohols.These transformations are accomplished by the action of telluride ion, generated in situ from the element, on a glycidyl sulfonate ester.Reduction of elemental Te is conveniently done with rongalite (HOCH2SO2Na) in an aqueous medium.This method is satisfactory when Te2- is required to attack at primary carbon site of a glycidyl sulfonate.In cases where Te2- is required to attack a secondary carbon site, reduction of the tellurium must be done with NaBH4 or LiEt3BH.Elemental tellurium is precipitated during the course of the reactions and can be recovered and reused.
