Phase Transfer Reagent Promoted Tandem Ring-Opening and Ring-Closing Reactions of Unique 3‑(1-Alkynyl) Chromones

A phase transfer reagent promoted tandem ring-opening and ring-closing reaction of 3-(1-alkynyl) chromones has been developed. This process remarkably generates functionalized 3-acyl-2-substituted chromones. Interestingly, when 3-(hepta-1,6-diyn-1-yl)­chromone derivatives are applied, a novel tetracyclic chromone scaffold can be obtained by a further intramolecular 4 + 2 cyclization

Microwave Assisted Tandem Heck–Sonogashira Reactions of <i>N,N</i>-Di-Boc-Protected 6‑Amino-5-iodo-2-methyl Pyrimidin-4-ol in An Efficient Approach to Functionalized Pyrido[2,3‑<i>d</i>]Pyrimidines

A microwave assisted tandem Heck–Sonogashira cross-coupling reaction between 6-<i>N,N</i>-di-Boc-amino-5-iodo-2-methyl pyrimidin-4-ol and various aryl alkynyl substrates has been developed. This process generates novel 5-enynyl substituted pyrimidines, which can be transformed to novel functionalized pyrido­[2,3-<i>d</i>]­pyrimidines by way of a silver catalyzed cyclization reaction