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El acceso a la versión del editor puede requerir la suscripción del recurso Access to the published version may require subscription Synthesis of 5-/8-Halogenated or Ethynylated Lipophilic Nucleobases as Potential Synthetic Intermediates for Supramolecular ChemistryNerea Bilbao, [a] Violeta Vázquez-González, [a] M. Teresa Aranda, [a] and David González-Rodríguez* [a] Abstract: A series of lipophilic nucleobases that are substituted at the 5-(pyrimidines) or 8-position (purines) with either a halogen atom or a terminal triple bond have been synthesized. The sequences and reactions studied in this work, which mainly comprise halogenation, alkylation, Sonogashira coupling, and trimethylsilylacetylene deprotection, have been carefully optimized in order to reach the final compounds in the most straightforward, convenient way and with the maximum purity and yield. These compounds include cytosine, isocytosine and uracil as pyrimidine heterocycles, and guanine, isoguanine, and 2-aminoadenine as complementary purine bases.Variability was introduced at the N-1/N-9 positions of these pyrimidine/purine nucleobases, which were functionalized with alkyl or benzyl groups, as well as with protected amine or carboxylic acid substituents. The molecules prepared constitute a useful collection of synthetic intermediates in the field of chemical self-assembly.

A general and simple procedure for preparing any kind of enantiomerically enriched sulfoxide starting from norephedrine-derived N-benzyloxycarbonylsulfamidite 3a is reported. After one-pot reaction of 3a with RMgX, HBF(4), and R'MgX, a variety of sulfoxides 6 are obtained in ee usually higher than 93% and isolated yields ranging between 50 and 78%. The obtained configuration is tunable by simply electing the order of the addition of the reagents. [reaction--see text]

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