ABSTRACT
A novel Lewis acid catalyzed tandem cyclization reaction of internal alkynols and vinyl azides has been achieved to afford a series of products containing a pyran-based indeno[1,2-c]isochromene scaffold in moderate to high yields. This tandem polycyclization protocol provides a straightforward entry to construct the complex polycyclic skeleton through cycloisomerization, formal [4 + 2] cycloaddition, and an elimination process.
ABSTRACT
A copper(ii) perchlorate-promoted tandem reaction of internal alkynol and salicyl N-tosylhydrazone provides a novel, concise method for constructing isochromeno[3,4-b]chromene in 35-94% yields. The tandem reaction involves cycloisomerization, formal [4+2] cycloaddition and an elimination process.
Subject(s)
Alkynes/chemistry , Benzopyrans/chemical synthesis , Copper/chemistry , Hydrazones/chemistry , Perchlorates/chemistry , Benzopyrans/chemistry , Catalysis , Cycloaddition Reaction , Molecular Structure , X-Ray DiffractionABSTRACT
A tandem reaction of benzyne with functionalized benzylidenephthalan for the synthesis of a variety of phenanthro[10,1-bc]furans has been achieved for the first time in moderate to good yields. The reaction mechanism involves a DielsAlder reaction and an intermolecular nucleophilic addition reaction as the key steps.
