1552276-80-8

Upstream product

• 29558-78-9 4-hydroxy-4'-iodobiphenyl 
• 106-37-6 1.4-dibromobenzene 
• 994-30-9 triethylsilyl chloride 
• 1552276-77-3 C₄₂H₆₁BrO₃Si₃ 
• 116934-63-5 4-bromo-4'-[[(1,1-dimethylethyl)dimethylsilyl]oxy]-1,1'-biphenyl 
• 1552276-78-4 4'-[4-(4-bromophenyl)-1,4-bis(triethylsiloxy)-2,5-cyclohexadien-1-yl]-[1,1'-biphenyl]-4-ol 

Relevant academic research and scientific papers

Practical Synthesis of [n]Cycloparaphenylenes (n=5, 7-12) by H2SnCl4-mediated aromatization of 1,4-dihydroxycyclo-2,5-diene Precursors

Cyclic precursors of cycloparaphenylenes (CPPs) containing 1,4-dihydroxy-2,5-cyclohexadien-1,4-diyl units are prepared by modifying a synthetic method developed by Jasti and co-workers for the synthesis of corresponding 1,4-dimethoxy derivatives. Reductive aromatization of the diyl moieties by SnCl2/2 HCl takes place under mild conditions and affords the CPPs in good yields, incorporating 5 or 7-12 phenylene units. Highly strained [5]CPP is synthesized in greater than 0.3 g scale. 119Sn NMR spectroscopy clarifies the in situ formation of an ate complex, H2SnCl4, upon mixing a 2:1 ratio of HCl and SnCl2, which serves as a highly active reducing agent under nearly neutral conditions. When more than 2 equivalents of HCl, in relation to SnCl2, are used, acid-catalyzed decomposition of the CPP precursors takes place. The stoichiometry of HCl and SnCl2 is critical in achieving the desired aromatization reaction of highly strained CPP precursors. Behold the ring of rings: [n]Cycloparaphenylenes (n=5, 7-12) have been synthesized in good yields by reductive aromatization of cyclic precursors incorporating 1,4-dihydroxycyclo-2,5-diene units by employing H2SnCl4, which was prepared in situ by mixing SnCl2 and 2 equivalents of concentrated aqueous HCl.

Synthesis and characterization of [5]cycloparaphenylene

The synthesis of highly strained [5]cycloparaphenylene ([5]CPP), a structural unit of the periphery of C60 and the shortest possible structural constituent of the sidewall of a (5,5) carbon nanotube, was achieved in nine steps in 17% overall yield. The synthesis relied on metal-mediated ring closure of a triethylsilyl (TES)-protected masked precursor 1c followed by removal of the TES groups and subsequent reductive aromatization. UV-vis and electrochemical studies revealed that the HOMO-LUMO gap of [5]CPP is narrow and is comparable to that of C60, as predicted by theoretical calculations. The results suggest that [5]CPP should be an excellent lead compound for molecular electronics.