Marked leaving group strain in (Z)-2-ethylidenebicyclo[2.2.2]oct-1-yl triflate and its significant relief in (Z)-2-ethylidenebicyclo[3.2.2]non-1-yl mesylate

1991 ◽  
Vol 56 (17) ◽  
pp. 5007-5008 ◽  
Author(s):  
Kenichi Takeuchi ◽  
Yasushi Ohga ◽  
Toshikazu Kitagawa
Keyword(s):  
Leaving Group ◽  
Group Strain

Remarkably large solvolytic rate enhancement due to relief of ground state leaving group strain

1974 ◽  
Vol 96 (6) ◽  
pp. 1969-1970 ◽  
Author(s):  
Joel Slutsky ◽  
Richard C. Bingham ◽  
Paul V. R. Schleyer ◽  
W. C. Dickason ◽  
H. C. Brown
Keyword(s):  
Ground State ◽  
Rate Enhancement ◽  
Leaving Group ◽  
Group Strain

ChemInform Abstract: A REMARKABLY LARGE SOLVOLYTIC RATE ENHANCEMENT DUE TO RELIEF OF GROUND STATE LEAVING GROUP STRAIN

1974 ◽  
Vol 5 (22) ◽  
pp. no-no
Author(s):  
JOEL SLUTSKY ◽  
RICHARD C. BINGHAM ◽  
PAUL VON R. SCHLEYER ◽  
W. C. DICKASON ◽  
H. C. BROWN
Keyword(s):  
Ground State ◽  
Rate Enhancement ◽  
Leaving Group ◽  
Group Strain

General Cyclopropane Assembly via Enantioselective Redox-Active Carbene Transfer to Aliphatic Olefins

2018 ◽  
Author(s):  
Marc Montesinos-Magraner ◽  
Matteo Costantini ◽  
Rodrigo Ramirez-Contreras ◽  
Michael E. Muratore ◽  
Magnus J. Johansson ◽  
...  
Keyword(s):  
Total Synthesis ◽  
Asymmetric Synthesis ◽  
Chemical Space ◽  
Synthetic Approach ◽  
Asymmetric Cyclopropanation ◽  
Redox Active ◽  
Wide Range ◽  
Leaving Group ◽  
Stereoelectronic Properties ◽  
Carbene Transfer

Asymmetric cyclopropane synthesis currently requires bespoke strategies, methods, substrates and reagents, even when targeting similar compounds. This limits the speed and chemical space available for discovery campaigns. Here we introduce a practical and versatile diazocompound, and we demonstrate its performance in the first unified asymmetric synthesis of functionalized cyclopropanes. We found that the redox-active leaving group in this reagent enhances the reactivity and selectivity of geminal carbene transfer. This effect enabled the asymmetric cyclopropanation of a wide range of olefins including unactivated aliphatic alkenes, enabling the 3-step total synthesis of (–)-dictyopterene A. This unified synthetic approach delivers high enantioselectivities that are independent of the stereoelectronic properties of the functional groups transferred. Our results demonstrate that orthogonally-differentiated diazocompounds are viable and advantageous equivalents of single-carbon chirons<i>.</i>

Allylic Amination via Acid Catalyzed Leaving Group Activation

2016 ◽  
Vol 3 (2) ◽  
pp. 145-159
Author(s):  
Marija Skvorcova ◽  
Aigars Jirgensons
Keyword(s):  
Allylic Amination ◽  
Leaving Group ◽  
Acid Catalyzed

The effect of steric size of leaving group on rates of the competing syn- and anti-pathways in biomolecular elimination

1980 ◽  
Vol 45 (8) ◽  
pp. 2171-2178
Author(s):  
Jiří Závada ◽  
Magdalena Pánková
Keyword(s):  
Comparative Analysis ◽  
Homologous Series ◽  
Leaving Group ◽  
Leaving Groups

Approximate rates of the competing syn- and anti-pathways have been determined in t-C4H9OK-t-C4H9OH promoted elimination from two homologous series of tosylates: I-OTs trans-III (R = H, CH3, C2H5, n-C3H7, i-C3H7, t-C4H9) and II-OTs trans-IV (R = CH3, C2H5, n-C3H7, i-C3H7, t-C4H9). A comparison has been made with rates of the same processes in the (+) elimination of the corresponding trimethylammonium salts I-N(CH3)3 trans-III and (+) II-N(CH3)3 trans-IV. The title effect is demonstrated by a comparative analysis of the rate patterns obtained for the two leaving groups.

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