Chemical Structure from Scientific Research

Scope of the monoarylation reaction. This method allows access to the three types of lower helicenes with various substitution patterns in high yields and enantioselectivities and is applicable to azahelicenes. Standard reagents and conditions: 1 (0.1 mmol, 1.0 equiv.), Pd 2 dba 3 (5 mol%), ligand (20 mol%), Cs 2 CO 3 (0.5 equiv.), CPME (1 ml), T C, 24 h. The X-ray crystallographic structures of 2p and 2q are shown. a Free energy of enantiomerization computed at the B3LYP-D3(BJ)/6-311G(d,p) level of theory. b Experimental enantiomerization barrier measured at 120 C. c Thermal ellipsoids are shown at the 50% probability level. d Thermal ellipsoids are shown at the 20% probability level.

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