Resolution of inherently chiral anti-O,O′-dialkylthiacalix[4]arenes and determination of their absolute stereochemistries

Inherently chiral anti-O,O′-dibenzyl- and anti-O,O′-dibutyl-p-tert-butylthiacalix[4]arenes 4 and 6 are resolved as (S)-2-methoxy-2-(naphthalen-1-yl)propionic esters by flash chromatography. The absolute stereochemistries were determined to be (Sa)-(+)-4 and (Sa)-(+)-6 by X-ray crystallographic analyses.

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(Sa)-anti-25,26-Bis(benzyloxy)-5,11,17,23-tetra-tert-butyl-27,28-dihydroxythiacalix[4]areneC54H60O4S4Ee = 99.9%[α]D28=+4.5 (c 1.00, chloroform)Absolute configuration: Sa

(Sa)-anti-25,26-Dibutoxy-5,11,17,23-tetra-tert-butyl-27,28-dihydroxythiacalix[4]areneC48H64O4S4Ee = 99.8%[α]D27=+16.3 (c1.00, chloroform)Absolute configuration: Sa