The effect of DMSO on the borohydride reduction of a cyclohexanone: A formal enantioselective synthesis of (+)-epibatidine
摘要:
An asymmetric synthesis of (+)-epibatidine is described which uses the increased stereoselectivity of a borohydride reduction induced by the presence of DMSO. (C) 1998 Elsevier Science Ltd. All rights reserved.
Facile biocatalytic syntheses of optically active 4-hydroxycyclohex-2-enone and 4-benzylthiacyclopent-2-enone
摘要:
Novozyme 435(R) (Candida antarctica Lipase B) effects the kinetic resolution of both 3-benzylthia-4-hydroxycyclopentanone and its six-membered ring analogue, providing a novel route to both enantiomers of 4-benzylthiacyclopent-2-enone and the two enantiomers of 4-hydroxycyclohex-2-enone, all in a state of very high optical purity. (C) 2004 Elsevier Ltd. All rights reserved.
Development of a β-C–H Bromination Approach toward the Synthesis of Jerantinine E
作者:Tatjana Huber、Teresa A. Preuhs、Christa K. G. Gerlinger、Thomas Magauer
DOI:10.1021/acs.joc.7b01095
日期:2017.7.21
The development of an asymmetric and highly convergent three-component synthesis of the functionalized ABC ring system of the Aspidosperma alkaloid jerantinine E is reported. The presented synthetic strategy relies on our recently developed method for the one-pot β-C–H bromination of enones, which allows for rapid construction of the tricyclic tetrahydrocarbazolone core via a palladium-catalyzed amination
Cyclobutane Synthesis and Fragmentation. A Cascade Route to the <i>Lycopodium</i> Alkaloid (−)-Huperzine A
作者:James D. White、Yang Li、Jungchul Kim、Miroslav Terinek
DOI:10.1021/acs.joc.5b01619
日期:2015.12.4
asymmetric total synthesis of the nootropic alkaloid (−)-huperzine A was completed using a cascade sequence initiated by an intramolecular aza-Prins reaction and terminated by a stereoelectronically guided fragmentation of a cyclobutylcarbinyl cation as the key step in assembling the bicyclo[3.3.1]nonene core of the natural product. Intramolecular [2 + 2]-photocycloaddition of the crotyl ether of (S)-4-h
A Novel Synthesis of (−)-Huperzine A via Tandem Intramolecular Aza-Prins Cyclization–Cyclobutane Fragmentation
作者:James D. White、Yang Li、Jungchul Kim、Miroslav Terinek
DOI:10.1021/ol400012s
日期:2013.2.15
The acetylcholinesterase inhibitor (−)-huperzine A was synthesized from (S)-4-hydroxycyclohex-2-enone in 17 steps by a route that involved two cyclobutane fragmentations. The first of these employed a retro-aldol cleavage to generate the α-pyridone ring of huperzine A, and the second invoked a novel intramolecular aza-Prins reaction in tandem with stereocontrolled scission of a cyclobutylcarbinyl cation
Mn-salen catalyzed asymmetric oxidation of enol derivatives
作者:Tsutomu Fukuda、Tsutomu Katsuki
DOI:10.1016/0040-4039(96)00858-1
日期:1996.6
Mn-salen complex 1 was found to catalyze highly enantioselective oxidation of enol ethers with iodosylbenzene as a terminal oxidant giving the corresponding hydroxy acetals, when the reaction was carried out in an alcoholic solvent. The reactions in the usual solvents such as dichloromethane and acetonitrile showed irregular and lower enantioselectivity, partly due to racemization of the resulting
An Efficient Protocol for the Enantioselective Preparation of a Key Polyfunctionalized Cyclohexane. New Access to (<i>R</i>)- and (<i>S</i>)-4-Hydroxy-2-cyclohexenone and (<i>R</i>)- and (<i>S</i>)-<i>trans</i>-Cyclohex-2-ene-1,4-diol
作者:Pau Bayón、Georgina Marjanet、Gladis Toribio、Ramon Alibés、Pere de March、Marta Figueredo、Josep Font
DOI:10.1021/jo800107h
日期:2008.5.1
accessible raw materials such as p-methoxyphenol, ethylene glycol, and thiophenol, a protocol has been developed to prepare multigram quantities of the polyfunctionalized cyclohexane (±)-7. A highly efficient resolution of (±)-7 has been achieved through enantioselective acetylation catalyzed by Candida antarctica lipase B. Straightforward and enantioselective syntheses of 4-hydroxy-2-cyclohexenone, 1