ChemInform Abstract: 1994 Merck Frosst Award Lecture. New Strategies for the Stereoselective Synthesis of Natural and Unnatural Products via Organometallic Reagents and Catalysts

ChemInform ◽  
2010 ◽  
Vol 27 (13) ◽  
pp. no-no
Author(s):  
M. LAUTENS ◽  
Y. REN ◽  
P. DELANGHE ◽  
P. CHIU ◽  
S. MA ◽  
...  
Keyword(s):  
Stereoselective Synthesis ◽  
Organometallic Reagents ◽  
Unnatural Products ◽  
New Strategies

1994 Merck Frosst Award Lecture New strategies for the stereoselective synthesis of natural and unnatural products via organometallic reagents and catalysts

1995 ◽  
Vol 73 (8) ◽  
pp. 1251-1257 ◽  
Author(s):  
Mark Lautens ◽  
Yi Ren ◽  
Patrick Delanghe ◽  
Pauline Chiu ◽  
Shihong Ma ◽  
...  
Keyword(s):  
Lewis Acid ◽  
Palladium Catalyst ◽  
Stereoselective Synthesis ◽  
Nickel Catalysts ◽  
X Ray Diffraction ◽  
Organometallic Reagents ◽  
Intramolecular Cycloaddition ◽  
X Ray ◽  
Acid Lactone ◽  
New Strategies

Samarium in the presence of diiodomethane selectively cyclopropanates an allenic alcohol to yield a methylenecyclopropane with modest to excellent diastereoselectivity. The effect of substituents at the carbinol carbon and the allenic carbon on the diastereoselectivity was investigated. A palladium catalyst was shown to promote the intramolecular cycloaddition of the methylenecyclopropane with an electron-deficient alkyne to yield a methylenecyclopentane. The reaction was stereospecific with retention of stereochemistry as proven by X-ray diffraction. Nickel catalysts accelerate the hydroalumination of oxabicyclo[3.2.1]alkenes, leading to bicyclic trialkylalanes. Upon treatment with a Lewis acid (diisobutylaluminum chloride), the trialkylalanes fragment to provide cycloheptenols. This reaction, followed by an enantioselective enzyme-catalyzed esterification, was used as a key step in a synthesis of the mevinic acid lactone. Keywords: methylenecyclopropane, palladium, stereocontrol, oxabicyclic, nickel.

Enantioselective Multi-Component Cyclopropane Synthesis Enabled by Cu-Catalyzed Cyclopropene Carbometallation with Organoboron Reagent

2018 ◽  
Author(s):  
Zhanyu Li ◽  
Mengru Zhang ◽  
Yu Zhang ◽  
Shuang Liu ◽  
Jinbo Zhao ◽  
...  
Keyword(s):  
Carbon Source ◽  
Stereoselective Synthesis ◽  
Organometallic Reagents ◽  
Preliminary Results ◽  
Quaternary Center ◽  
Chiral Centers ◽  
Substituted Cyclopropanes ◽  
Proof Of Principle

Deployment of organoboron in lieu of the strongly basic <br>organometallic reagents as carbon source in Cu-catalyzed <br>cyclopropene carbometallation opens unprecedented three-<br>component reactivity for stereoselective synthesis of poly-substituted cyclopropanes. A proof-of-principle demonstration of this novel carbometallation strategy is presented herein for a highly convergent access to poly-substituted aminocyclopropane framework via <br>carboamination. Preliminary results on asymmetric desymmetrization with commercial bisphosphine ligands attained high levels of enantioselection, offering a straightforward access to enantioenriched aminocyclopropanes bearing all-three chiral centers, including an all-carbon quaternary center. This strategy may underpin a host of novel synthetic protocols for poly-substituted cyclopropanes. <br>

Stereoselective Synthesis of All-Carbon Tetrasubstituted Alkenes from In Situ Generated Ketenes and Organometallic Reagents

2013 ◽  
Vol 15 (7) ◽  
pp. 1610-1613 ◽  
Author(s):  
Wei You ◽  
Yan Li ◽  
M. Kevin Brown
Keyword(s):  
Stereoselective Synthesis ◽  
Organometallic Reagents

Stereoselective Synthesis of 3-Substituted and 3,4-Disubstituted Piperidine und Piperidin-2-one Derivatives

2012 ◽  
Vol 67 (4) ◽  
pp. 389-405 ◽  
Author(s):  
Ellen Klegraf ◽  
Horst Kunz
Keyword(s):  
Nucleophilic Addition ◽  
Stereoselective Synthesis ◽  
Organometallic Reagents

The stereoselective synthesis of 3-substituted and 3,4-disubstituted piperidine and piperidin-2-one derivatives was achieved starting from 2-pyridone. After N-galactosylation and subsequent O-silylation, nucleophilic addition of organometallic reagents proceeded with high regio- and stereoselectivity at 4-position. Substituents at position 3 were stereoselectively introduced by reaction of electrophiles with amide enolates of the N-galactosyl-2-piperidones.

Stereoselective synthesis of 2Z, 4E-dienals by addition of organometallic reagents to pyrylium perchlorate

1989 ◽  
pp. 683 ◽  
Author(s):  
Mark Furber ◽  
John M. Herbert ◽  
Richard J. K. Taylor
Keyword(s):  
Stereoselective Synthesis ◽  
Organometallic Reagents
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