p-TsOH promoted synthesis of benzo-fused O-heterocycles from alkynols via ring contraction and C–O scission strategy?

Green Chemistry Pub Date: 2018-06-18 DOI: 10.1039/C8GC00749G

Abstract

Here, we report the first divergent synthesis of benzo-fused O-heterocycles by p-toluene sulfonic acid promoted cascade reactions involving alkyne hydration, double cyclization, ring contraction and C–O bond cleavage from alkynols. The reaction mechanism was validated by obtaining the X-ray structure of fused benzo[b]oxepine intermediates. Moreover, some of the obtained derivatives could be transformed into 2,3-disubstituted naphthoquinones as important structural motifs in natural products and bioactive molecules.

Graphical abstract: p-TsOH promoted synthesis of benzo-fused O-heterocycles from alkynols via ring contraction and C–O scission strategy
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