Iodobenzene-catalyzed synthesis of α,α′-dihydroxy ketones: In situ generation of [bis(trifluoroacetoxy)iodo]benzene
摘要:
Exposure of ethynyl carbinols to oxone/(CF3CO)(2)O in the presence of a catalytic amount of iodobenzene afforded ,-dihydroxy ketones in good yield, which are common structural motifs in natural products and biologically active compounds. Compared with traditional methods, this method is more convenient and avoids using stoichiometric amounts of hypervalent iodine reagents.
Kinetic Resolution of Tertiary Propargylic Alcohols by Enantioselective Cu−H-Catalyzed Si−O Coupling
作者:Jan Seliger、Xichang Dong、Martin Oestreich
DOI:10.1002/anie.201813229
日期:2019.2.11
A broad range of tertiary propargylic alcohols were kinetically resolved by catalyst‐controlled enantioselective silylation. This non‐enzymatic kineticresolution is catalyzed by a Cu−H species and makes use of the commercially available precatalyst MesCu/(R,R)‐Ph‐BPE and a simple hydrosilane as the resolving reagent. Both alkyl,aryl‐ as well as dialkyl‐substituted propargylic alcohols participate
(Diacetoxyiodo)benzene-Mediated Reaction of Ethynylcarbinols: Entry to α,α′-Diacetoxy Ketones and Glycerol Derivatives
作者:Qing-Rong Liu、Cheng-Xue Pan、Xiao-Pan Ma、Dong-Liang Mo、Gui-Fa Su
DOI:10.1021/acs.joc.5b00740
日期:2015.6.19
Efficient access to α,α′-diacetoxy ketones has been developed from ethynylcarbinols and PhI(OAc)2. A plausible mechanism for this was proposed on the basis of experimental studies. The usefulness of α,α′-diacetoxy ketone products has been documented, and glycerol derivatives can be easily synthesized in good yields via a one-potreaction.
A recombinant Bacillus subtilis esterase (BsE) expressed in E. coli was found to exhibit excellent enantioselectivity (E was always greater than 100) towards m-substituted 1-phenylethanol acetates in the enantioselective hydrolysis reaction. An explanation for the high enantioselectivity observed towards these substrates was provided by molecular modeling. Moreover, the BsE also showed strong tolerance towards a high concentration of m-substituted 1-phenylethanol acetates (up to 1 M). Based on these excellent catalytic properties of BsE, a kind of m-substituted 1-phenylethanols, (R)-1-(3-chlorophenyl)ethanol, was efficiently synthesized in space-time yield of 920 g per L per day and 97% ee, indicating that the BsE was considered as a potentially ideal and promising biocatalyst for large-scale production of optically active m-substituted 1-phenylethanols.
Enantioselective transesterification of a tertiary alcohol by lipase A from Candida antarctica
作者:Sajja Hari Krishna、Mattias Persson、Uwe T Bornscheuer
DOI:10.1016/s0957-4166(02)00739-5
日期:2002.12
Chiral tertiaryalcohols and their esters represent important flavor compounds and are useful building blocks. Unfortunately, they are accepted by only a few lipases/esterases as substrates and enantioselectivity is usually very low. We report here a highlyenantioselective transesterification of the tertiaryalcohol 2-phenylbut-3-yn-2-ol using lipase A from Candida antarctica (CAL-A). Under optimized
A facile synthesis of β-allenyl furanimines via Pd-catalyzed cyclization of 2,3-allenamides with propargylic carbonates
作者:Guofei Chen、Ya Zhang、Chunling Fu、Shengming Ma
DOI:10.1016/j.tet.2011.01.041
日期:2011.3
The Pd(OAc)(2)/TFP-catalyzed cyclization reaction of 2,3-allenamides in the presence of propargylic carbonates provides an efficient route to beta-allenyl furanimine derivatives. Preliminary mechanistic study showed that this reaction was probably initiated by Pd(0) species. (C) 2011 Elsevier Ltd. All rights reserved.