- Versatile C(sp2)?C(sp3) Ligand Couplings of Sulfoxides for the Enantioselective Synthesis of Diarylalkanes
-
The reaction of chiral (hetero)aryl benzyl sulfoxides with Grignard reagents affords enantiomerically pure diarylalkanes in up to 98 % yield and greater than 99.5 % enantiomeric excess. This ligand coupling reaction is tolerant to multiple substitution patterns and provides access to diverse areas of chemical space in three operationally simple steps from commercially available reagents. This strategy provides orthogonal access to electron-deficient heteroaromatic compounds, which are traditionally synthesized by transition metal catalyzed cross-couplings, and circumvents common issues associated with proto-demetalation and β-hydride elimination.
- Dean, William M.,?iau?iulis, Mindaugas,Storr, Thomas E.,Lewis, William,Stockman, Robert A.
-
p. 10013 - 10016
(2016/08/16)
-
- Photostimulated Reactions of 2-Bromopyridine and 2-Chloroquinoline with Nitrile-Stabilized Carbanions and Certain Other Nucleophiles
-
Potassiophenylacetonitrile (2) reacts with 2-bromopyridine (1) and 2-chloroquinoline (4) via the SRN1 mechanism when the reactants are exposed to near-UV light in liquid NH3.Potassioacetonitrile (6) reacts similarly with 1 and 4 upon photostimulation; however, the photo-SRN1 reaction with 1 is accompanied by SNAr2 amination which becomes the major reaction in the dark or in the presence of di-tert-butyl nitroxide.Substrate 4 undergoes competing SNAr2 amination with amide ion to form 2-aminoquinoline (10) and SN(ANRORC) reactions with both amide ion and carban ion 6 to form 3-methylquinazoline (11) and 2-methyl-3-cyanoquinoline (12), respectively.Formation of 12 becomes the major pathway in reactions between 4 and 6 carried out in the dark. 4-Picolylpotassium (14) reacts with 1, 4, and 4-bromopyridinium chloride (16) under photostimulation to form the appropriate dihetarylmethanes, along with the corresponding amino heterocycles.Amination of 1, 4, and 16 predominates when these reactions are carried out in the dark.Ammonium thiophenoxide (20) undergoes a slow photo-SRN1 reaction with 1 but fails to produce the expected 2-quinolyl phenyl sulfide with 4 after 2 h of irradiation.Potassium salts of acetylene, phenylacetylene, and phthalimide do not react with 1 or 4 after 2 h of exposure to near-UV light.
- Moon, Marcus P.,Komin, Andrew P.,Wolfe, James F.,Morris, Gene F.
-
p. 2392 - 2399
(2007/10/02)
-