Stereoselective Synthesis of 5-(1-Hydroxyalkyl)-2-pyrrolidinones Utilizing Oxidation of 5-Alkylidene-2-pyrrolidinones to Acyliminium Ion Precursors
摘要:
A general method was devised for the LiN(TMS)(2)/AgOTf (=2:1)-catalyzed intramolecular (5-exo-dig) cyclization of beta -alkynylamides 1 possessing alkyl, aryl or no functional groups at the terminal alkynes, to 5-alkylidene-2-pyrrolidinones 2. These 5-alkylidene-2-pyrrolidinones were oxidized to the diol-type alkoxylactams 3 by dimethyldioxirane (DMD) or mCPBA in MeOH. These alkoxylactams are useful as tertiary N-acyliminium ion precursors for the synthesis of threo-5-(1-hydroxyalkyl)-2-pyrrolidinone derivatives 5. (C) 2000 Elsevier Science Ltd. All rights reserved.
Stereoselective Synthesis of 5-(1-Hydroxyalkyl)-2-pyrrolidinones Utilizing Oxidation of 5-Alkylidene-2-pyrrolidinones to Acyliminium Ion Precursors
摘要:
A general method was devised for the LiN(TMS)(2)/AgOTf (=2:1)-catalyzed intramolecular (5-exo-dig) cyclization of beta -alkynylamides 1 possessing alkyl, aryl or no functional groups at the terminal alkynes, to 5-alkylidene-2-pyrrolidinones 2. These 5-alkylidene-2-pyrrolidinones were oxidized to the diol-type alkoxylactams 3 by dimethyldioxirane (DMD) or mCPBA in MeOH. These alkoxylactams are useful as tertiary N-acyliminium ion precursors for the synthesis of threo-5-(1-hydroxyalkyl)-2-pyrrolidinone derivatives 5. (C) 2000 Elsevier Science Ltd. All rights reserved.
Directed Regioselective Carbometallation of 1,2‐Dialkyl‐Substituted Cyclopropenes
作者:Yair Cohen、Ilan Marek
DOI:10.1002/anie.202111382
日期:2021.12.6
The copper-catalyzedcarbomagnesiation reaction of cyclopropenes is a well-established method for the synthesis of stereodefined cyclopropanes. All existing reports to date proceeded towards the formation of the electronically more stable organometallic intermediate. Herein we report a regioselective addition to 1,2-dialkyl-substituted cyclopropene possessing a tethered directing group to direct the
in a highly regioselective manner. Their subsequent reaction with sulfonylacetylene afforded pyridyltitanium compounds, which, upon reaction with electrophiles, gave substituted pyridines virtually as a single isomer. When opticallyactive nitriles were used in this reaction, chiral pyridines were obtained without loss of the enantiopurity. Alternatively, the azatitanacyclopentadiene prepared from an
Nickel(0)-catalyzed synthesis of substituted phenols from cyclobutenones and alkynes
作者:Mark A. Huffman、Lanny S. Liebeskind
DOI:10.1021/ja00007a072
日期:1991.3
The results above show that the convergent synthesis of substituted phenols is possible by nickel(0)-catalyzed ring opening and cycloaddition of cyclobutenones with alkynes. Future efforts will explore application of this method to intramolecular reactions
Rhodium/Lewis Acid Catalyzed Regioselective Addition of 1,3-Dicarbonyl Compounds to Internal Alkynes
作者:Wei-Feng Zheng、Qiu-Jing Xu、Qiang Kang
DOI:10.1021/acs.organomet.7b00284
日期:2017.6.26
regioselective addition of 1,3-dicarbonyl compounds to internal alkynescatalyzed by rhodium/Lewisacid catalysts. The corresponding branched/linear allylic alkylation products could be selectively obtained in good yields. Rh–H species were considered to be generated by direct C–H oxidative addition of 1,3-dicarbonyl compounds with rhodium catalyst with the assistance of Lewisacid. Moreover, a retro-allylic
Tandem Rh-catalysis: decarboxylative β-keto acid and alkyne cross-coupling
作者:Faben A. Cruz、Zhiwei Chen、Sarah I. Kurtoic、Vy M. Dong
DOI:10.1039/c6cc02522f
日期:——
Herein, we describe a regioselective Rh-catalyzed decarboxylative cross-coupling of [small beta]-keto acids and alkynes to access branched [gamma],[small delta]-unsaturated ketones. Rh-hydride catalysis enables the isomerization of an alkyne to generate a metal-allyl...