ChemInform Abstract: Enantioselective Ring Opening of meso‐Epoxides with Silicon Tetrachloride Catalyzed by Pyridine N‐Oxides Fused with the Bicyclo[3.3.1]nonane Framework.

Heteroaromatic N-Oxides in Asymmetric Catalysis: A Review

“…Mostly, they are used in the synthesis of numerous natural products as building blocks but also in the synthesis of drug candidates and other functional molecules [11][12][13][14][15][16][17]. Apart from allylation there were also reported examples of using N-oxides in the catalytic ring-opening of meso-epoxides [18][19][20][21], propargylation [22], allenylation [23], aldol reaction [24,25] and reduction of ketoimines [26,27].…”

“…Another synthetic strategy was taken for 14e, which the authors briefly explained in the published work [9a]. The Ramanathan group has tested the versatility of prepared derivatives as Lewis basic activators in the desymmetrization reaction of meso-epoxides with silicon tetrachloride [18]. Catalysts 12 applied in the reaction with cis-stilbene epoxide were not very selective (12a gave 32% ee, 12b-5% ee and 12i-42% ee).…”

“…Another synthetic strategy was taken for 14e, which the authors briefly explained in the published work Stončius and Neniškis presented a completely different approach. The Lewis bases were invented, in which the pyridine N-oxide unit has been attached to a chiral bicyclo [3.3.1] nonane backbone [18]. Authors designed the structures, that contain two 2,4-diaryl-substituted pyridine N-oxide moieties 14 and corresponding monofunctional congeners 15 (see Figure 2).…”