Mimicking the First Step of RNA Splicing:  An Artificial DNA Enzyme Can Synthesize Branched RNA Using an Oligonucleotide Leaving Group as a 5‘-Exon Analogue†

Biochemistry ◽  
2005 ◽  
Vol 44 (41) ◽  
pp. 13439-13446 ◽  
Author(s):  
Rebecca L. Coppins ◽  
Scott K. Silverman
Keyword(s):  
Rna Splicing ◽  
Leaving Group ◽  
Artificial Dna ◽  
Branched Rna

Time-of-flight Secondary Ion Mass Spectrometry of Branched RNA Fragrants: Messenger RNA Splicing Intermedistes

1990 ◽  
Vol 9 (3) ◽  
pp. 445-446 ◽  
Author(s):  
Francois Lafortune ◽  
Masad J. Damha ◽  
Xuejun Tang ◽  
Kenneth G. Standing ◽  
John B. Westmore ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Rna Splicing ◽  
Messenger Rna ◽  
Secondary Ion Mass Spectrometry ◽  
Time Of Flight ◽  
Ion Mass Spectrometry ◽  
Branched Rna ◽  
Secondary Ion

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>

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