Chemoselective oxidation of phenoxathiin-based thiacalix[4]arene and the stereoselective alkylation of products

Abstract

Phenoxathiin-based thiacalix[4]arene was subjected to exhaustive oxidation. Depending on the reaction conditions, the macrocyclic systems bearing four sulfonyl groups or three sulfonyl and one sulfoxide group are available in high yields.

Enantiodiscrimination of Inherently Chiral Thiacalixarenes by Residual Dipolar Couplings

“…Compounds used for this study were obtained following a recently developed synthetic methodology leading to the phenoxathiin-based thiacalix[4]arene derivatives. − As shown in Scheme , starting tetrasulfone I was alkylated by the corresponding alkyl iodides in the presence of Cs 2 CO 3 to provide the peralkylated derivatives 1 and II in very good yields (84–89%). As recently reported, the reaction of 1 with sodium methoxide in THF led smoothly to the cleaved product III in 74% yield .…”

“…For 1 , we obtained seven or eight 1 D CH values for both enantiomers ( E1 and E2 ) (see Tables S5–S13); two values corresponding to the rotating t -butyl groups were converted to one-bond C–C 1 D CC the RDC between methyl and tertiary carbon nuclei . The RDC@hotFCHT software fitting procedure undoubtedly confirmed PaCoD as the best-fitting structure for both enantiomers E1 and E2 (Table ), which is in accordance with the X-ray structure …”

“…Excellent results were obtained (Table 2, last column) also by the fitting on the crystal structure (PaCoD). 21 Having calculated the alignment tensors, we could investigate the level of differences between the two enantiomers. A generalized dot product of two matrices (generalized angle β) 53 evaluated in our case to a moderate value of 22.6°(the bigger, the more different alignment tensors).…”

“…We have recently developed a synthetic methodology to produce phenoxathiin-based thiacalix[4]arene derivatives. − Compound 1 is an example of a macrocycle bearing a fused heterocyclic moiety that imparts considerable rigidity to the system. On the other hand, compound 2 displays more structural flexibility (Figure ) due to the cleavage of the oxygen bridge.…”

Recent Advances in Heterocyclic Nanographenes and Other Polycyclic Heteroaromatic Compounds

“…Lhoták and co-workers reported the phenoxathiin-based thiacalix[4]­arene C41.3a , which was accessed via an acid-catalyzed rearrangement of a spirodienone derivative, obtained by oxidation of thia[4]­calixarene with chloramine-T. − The inherently chiral C41.3a was alkylated, which led to the configurationally stable derivatives C41.3b , c with stereoselective formation of a partial cone conformer, which was determined using NMR and XRD analyses.…”