How does the use of different reducing agents (low-valent titanium vs. sodium naphthalenide) affect the synthesis of [6]CCHPB and its C2-symmetric congener?

The synthesis of [6]CCHPB and its C2-symmetric congener involves reductive aromatization, which can be influenced by the choice of reducing agent. Low-valent titanium and sodium naphthalenide were used in a study.

The choice of reducing agent significantly affects the outcome of the synthesis. Low-valent titanium, used at elevated temperatures (80°C), led to the formation of the hexaphenylbenzene cyclohexamer ([6]CCHPB). In contrast, sodium naphthalenide, used at a milder temperature (-78°C), resulted in the formation of the C2-symmetric congener. The difference in thermal energy (ΔT = 160°C) suggests that the reaction is kinetically controlled, with the milder conditions favoring the formation of the less strained C2-symmetric congener.