60410-16-4Relevant articles and documents
A method for high-throughput screening of enantioselective catalysts
Reetz, Manfred T.,Becker, Michael H.,Klein, Heinz-Werner,Stoeckigt, Detlef
, p. 1758 - 1761 (1999)
About 1000 catalytic or stoichiometric asymmetric reactions of racemic compounds or prochiral substrates bearing enantiotopic groups can be analyzed per day. In this highly efficient method the enantioselectivity is determined by electrospray ionization mass spectrometry using isotopically labeled substrates. The picture shows the mass spectrum of the mixture obtained upon hydrolysis of 1 to afford the pseudo-enantiomeric products 2 and 3.
Studies towards the total synthesis of an epoxy isoprostane phospholipid, a potent activator of endothelial cells.
Jung, Michael E,Kers, Annika,Subbanagounder, Ganesamoorthy,Berliner, Judith A
, p. 196 - 197 (2003)
We report studies toward the total synthesis of an epoxy isoprostane, namely the preparation of compound 9 which is an analogue of the elimination product 7 of the naturally occurring epoxy isoprostane 4 by a straightforward route using a three-component coupling, and have shown by several spectroscopic criteria that it closely resembles the natural material.
PALLADIUM-CATALYZED INTRAMOLECULAR OLEFIN ALLYLATIONS: STEREOCONTROLLED SYNTHESES OF BICYCLIC SYSTEMS AND EVIDENCE FOR AN ALLYLPALLADIUM/OLEFIN-CIS-INSERTION
Oppolzer, Wolfgang,Gaudin, Jean-Marc,Birkinshaw, Timothy N.
, p. 4705 - 4708 (1988)
Pd(0)-catalyzed cyclizations of (1-acetoxy-3-alkenyl)-2-cycloalkenes 3, 6 and 12 provide bicyclic systems in high diastereo- (5, 8) and enantio-meric (14) purity consistent with a predominant allylpalladium/alkene cis- insertion.
A HIGHLY ENANTIOSELECTIVE HYDROLYSIS OF CIS-3,5-DIACETOXYCYCLOPENT-1-ENE. AN ENZYMATIC PREPARATION OF 3(R)-ACETOXY-5(S)-HYDROXYCYCLOPENT-1-ENE.
Deardorff, Donald R.,Matthews, A. J.,McMeekin, D. Scott,Craney, Chris L.
, p. 1255 - 1256 (1986)
Exposure of cis-3,5-diacetoxycyclopent-1-ene (3) to the hydrolase enzyme acetylcholinesterase (from electric eel) affords in 94percent yield 3(R)-acetoxy-5(S)-hydroxycyclopent-1-ene (2) with an e.e. of 96percent (greater than 99percent e.e. after one recrystallization).
Total Synthesis of the Alleged Structure of Crenarchaeol Enables Structure Revision**
Cunha, Ana V.,Havenith, Remco W. A.,Holzheimer, Mira,Minnaard, Adriaan J.,Schouten, Stefan,Sinninghe Damsté, Jaap S.
supporting information, p. 17504 - 17513 (2021/07/06)
Crenarchaeol is a glycerol dialkyl glycerol tetraether lipid produced exclusively in Archaea of the phylum Thaumarchaeota. This membrane-spanning lipid is undoubtedly the structurally most sophisticated of all known archaeal lipids and an iconic molecule in organic geochemistry. The 66-membered macrocycle possesses a unique chemical structure featuring 22 mostly remote stereocenters, and a cyclohexane ring connected by a single bond to a cyclopentane ring. Herein we report the first total synthesis of the proposed structure of crenarchaeol. Comparison with natural crenarchaeol allowed us to propose a revised structure of crenarchaeol, wherein one of the 22 stereocenters is inverted.
Enantioselective Total Synthesis of (+)-Nordasycarpidone, (+)-Dasycarpidone, and (+)-Uleine
Delayre, Bastien,Fung, Cédric,Wang, Qian,Zhu, Jieping
, (2021/07/12)
The structure of uleine type alkaloids is characterized by the presence of a bridged tetracyclic hexahydro-1H-1,5-methanoazocino[4,3-b]indole ring system 1. Various strategies have been developed to access this polycyclic structural motif. We report herein a one-step conversion of appropriately functionalized 1,3,4-trisubstituted cyclopent-1-ene to 1 by way of an integrated oxidation/reduction/cyclization (iORC) process. This domino sequence, initiated by oxidative cleavage of cyclopentene ring, generated subsequently a cyclohexenone, an indole and a 1,3-bridged piperidine ring through formation of one C?C and two C?N bonds. Compound 1 is subsequently converted to nordasycarpidone, dasycarpidone and uleine. The chirality of the molecule was introduced by enzymatic desymmetrization of commercially available meso cis-3,5-diacetoxy-1-cyclopentene.
Acylative desymmetrization of cyclic meso-1,3-diols by chiral DMAP derivatives
Mandai, Hiroki,Hironaka, Tsubasa,Mitsudo, Koichi,Suga, Seiji
supporting information, p. 471 - 474 (2021/03/15)
An efficient enantioselective acylative desymmetrization of cyclic meso-1,3-diols was developed by using a chiral DMAP derivative 1e having a 1,1¤-binaphthyl unit. The reactions required only 0.5mol% of the catalyst and showed good to excellent enantioselectivity. With this transformation, 5a, a key building block for the synthesis of natural products, was easily obtained in almost enantiomerically pure form after a single recrystallization. Control experiments revealed that tert-alcohol units on the catalyst were responsible for both the catalytic activity and enantioselectivity.
Photo-oxidation of Cyclopentadiene Using Continuous Processing: Application to the Synthesis of (1 R,4 S)-4-Hydroxycyclopent-2-en-1-yl Acetate
Allais, Christophe,Herrero-Gomez, Elena,Huck, Lena,Keene, Nandell F.,Li, Bryan,Pouwer, Kees,Rioz-Martínez, Ana,Van Der Loo, Cornelis H. M.
, p. 2304 - 2310 (2020/11/23)
(1R,4S)-4-Hydroxycyclopent-2-en-1-yl acetate is a chiral small building block that was requested to advance several Pfizer programs into the clinic. Pfizer and Syncom partnered to develop a photo-oxidation process of cyclopentadiene using a flow approach followed by subsequent bis-acetylation of the meso diol and final biocatalytic desymmetrization. This continuous process was demonstrated on a 6 g·h-1 input and is amenable to larger scale. The optimization and scale-up of this sequence is described therein.
TiCl3-Mediated Synthesis of 2,3,3-Trisubstituted Indolenines: Total Synthesis of (+)-1,2-Dehydroaspidospermidine, (+)-Condyfoline, and (?)-Tubifoline
Delayre, Bastien,Piemontesi, Cyril,Wang, Qian,Zhu, Jieping
supporting information, p. 13990 - 13997 (2020/06/10)
2,3,3-Trisubstituted indolenine constitutes an integral part of many biologically important monoterpene indole alkaloids. We report herein an unprecedented access to this skeleton by a TiCl3-mediated reductive cyclization of tetrasubstituted alkenes bearing a 2-nitrophenyl substituent. The proof of concept is demonstrated firstly by accomplishing a concise total synthesis of (+)-1,2-dehydroaspidospermidine featuring a late-stage application of this key transformation. A sequence of reduction of nitroarene to nitrosoarene followed by 6π-electron-5-atom electrocyclization and a 1,2-alkyl shift of the resulting nitrone intermediate was proposed to account for the reaction outcome. A subsequent total synthesis of (+)-condyfoline not only illustrates the generality of the reaction, but also provides a mechanistic insight into the nature of the 1,2-alkyl shift. The exclusive formation of (+)-condyfoline indicates that the 1,2-alkyl migration follows a concerted Wagner–Meerwein pathway, rather than a stepwise retro-Mannich/Mannich reaction sequence. Conditions for almost quantitative conversion of (+)-condyfoline to (?)-tubifoline by way of a retro-Mannich/1,3-prototropy/transannular cyclization cascade are also documented.
Preparation of (1R,4S)-4-hydroxycyclopent-2-en-1-yl acetate via Novozym-435 catalyzed desymmetrization of cis-3,5-Diacetoxy-1-cyclopentene
Putta, Shekhar,Reddy, Annem Mallikarjun,Sheelu, Gurrala,Reddy, B.V. Subba,Kumaraguru, Thenkrishnan
, p. 6673 - 6679 (2018/10/15)
Photooxidation of cyclopentadiene has been carried out in methanol using white light of LED lamp, rose bengal as photo initiator, and compressed air at 0 °C. Under conditions of [thiourea] ? [cyclopentadiene], the consumption of thiourea follows a pseudo-first-order reaction kinetics with half life of 75 ± 10 min; corr. coeff. r = 0.989. Slow addition of the monomer and maintaining excess thiourea concentration in reaction mass improves the yield. cis-3,5-Dihydroxy-1-cyclopentene is acetylated without isolation to obtain cis-3,5-Diacetoxy-1-cyclopentene of high purity (>99%) with overall isolated yield of 30%. Desymmetrization of the diacetate to (1R,4S)-4-hydroxycyclopent-2-en-1-yl acetate has been carried out via enzymatic transesterification with methanol in methyl tert-butyl ether (MTBE) at 5 °C using Novozym-435. The enantiomerically pure monoacetate (e.e. >99%) was obtained in 95% isolated yield. The recovered enzyme was reused for more than 10 times without loss in yield and selectivity. The entire protocol does not require purification of final product by chromatography.
