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Unusual Calixarenes Incorporating Chromene and Benzofuran Moieties Obtained via Propargyl Claisen Rearrangement.

ABSTRACT: Monopropargyloxy-tripropoxy-calix[4]arene 1 was subjected to a propargyl Claisen rearrangement to give unusual calix[3]arene[1]chromene and homocalix[3]arene[1]benzofuran macrocycles. Quantum mechanical density functional theory calculations indicated that an initial [3,3] sigmatropic reaction affords a highly reactive allene intermediate, stabilized by two main diradical pathways leading to six- and five-membered oxygenated rings. In the presence of a n-butylammonium guest, calix[3]arene[1]chromane 6 forms two stereoisomeric complexes stabilized by ⁺N-H···O and cation···π interactions.

SUBMITTER: Soriente A

PROVIDER: S-EPMC8650102 | biostudies-literature | 2021 Dec

REPOSITORIES: biostudies-literature

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Unusual Calixarenes Incorporating Chromene and Benzofuran Moieties Obtained via Propargyl Claisen Rearrangement.

Soriente Annunziata A D'Acunto Mariantonietta M Talotta Carmen C Gaeta Carmine C Della Sala Paolo P De Rosa Margherita M Geremia Silvano S Hickey Neal N Rescifina Antonio A Neri Placido P

Organic letters 20211115 23

Monopropargyloxy-tripropoxy-calix[4]arene 1 was subjected to a propargyl Claisen rearrangement to give unusual calix[3]arene[1]chromene and homocalix[3]arene[1]benzofuran macrocycles. Quantum mechanical density functional theory calculations indicated that an initial [3,3] sigmatropic reaction affords a highly reactive allene intermediate, stabilized by two main diradical pathways leading to six- and five-membered oxygenated rings. In the presence of a n-butylammonium guest, calix[ ...[more]

PMID: 34779638

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