Pedersen, Stephan K. published the artcileSymmetric, Unsymmetrical, and Asymmetric [7]-, [10]-, and [13]Helicenes, Category: chlorides-buliding-blocks, the publication is Angewandte Chemie, International Edition (2019), 58(51), 18419-18423, database is CAplus and MEDLINE.
Fully aromatic helicenes with more than one pitch-length are illustrious synthetic targets with potential applications in advanced optical devices and nano-electronics. The task of extending the length of fully conjugated helicenes past one pitch length is challenging. Now, the synthesis of a series of azaoxa[7]-, [10]-, and [13]helicenes is described. The synthesis is based on iterative oxidative furan formation between 3,6-dihydroxycarbazoles and/or 2-naphthols [e.g., oxidative coupling of carbazole I to II followed by selective protection of least sterically hindered alcs. and furan formation mediated by oxidant and Lewis acid afforded diazaoxa[7]helicene III]. The flexibility of the presented method allows the convenient and scalable synthesis of sym., unsym., and asym. homo-chiral structures. The [13]helicenes can be synthetically functionalized both at the termini and the periphery. The full range of helicenes were characterized using NMR and optical spectroscopy (UV/Vis, fluorescence, and CD) along with single-crystal X-ray crystallog. The enantiomers of the [13]helicenes are the longest optically pure helicenes isolated to date.
Angewandte Chemie, International Edition published new progress about 21286-54-4. 21286-54-4 belongs to chlorides-buliding-blocks, auxiliary class Chiral,Chloride,Sulfonyl chlorides,Aliphatic cyclic hydrocarbon,Ketone, name is ((1S,4R)-7,7-Dimethyl-2-oxobicyclo[2.2.1]heptan-1-yl)methanesulfonyl chloride, and the molecular formula is C10H15ClO3S, Category: chlorides-buliding-blocks.
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