Iodine-mediated synthesis of benzo[a]fluorenones from yne-enones

The chalcones derived from o-alkynylacetophenones and aromatic aldehydes (yne-enones) when heated under reflux with iodine in acetic acid gave a range of benzo[a]fluorenone derivatives in moderate to good yields. The transformation involves the formation of a vinyl indenone intermediate through regioselective alkyne hydration and intramolecular aldol condensation followed by electrocyclic ring closure and aromatization.

An iodine mediated synthesis of benzo[a]fluorenone derivatives from the chalcones derived from o-alkynylacetophenones and aromatic aldehydes is described.

1,3-Dien-5-ynes: Versatile Building Blocks for the Synthesis of Carbo- and Heterocycles

1,3-Dien-5-ynes have been extensively used as starting materials for the synthesis of a wide number of different carbo- and heterocycles. The aim of this review is to give an overview of their utility in organic synthesis, highlighting the variety of compounds that can be directly accessed from single reactions over these systems. Thus, cycloaromatization processes are initially commented, followed by reactions directed toward the syntheses of five-membered rings, other carbocycles and, finally, heterocycles. The diverse methodologies that have been developed for the synthesis of each of these types of compounds from 1,3-dien-5-ynes are presented, emphasizing the influence of the reaction conditions and the use of additional reagents in the outcome of the transformations.

Iron(iii) halide or iodine-promoted synthesis of 3-haloindene derivatives from o-alkynylarene chalcones

The treatment of o-alkynylarene chalcones with ferric halides/iodine affords 3-haloindene derivatives in good yields.

Synthesis of 3,3-disubstituted-2,3-dihydroazanaphthoquinones via simultaneous alkyne oxidation and nitrile hydration of ortho-alkynylarenenitriles

Simultaneous activation of alkynes and nitriles in o-alkynylarenenitriles in the presence of Pd(OAc)₂/H₂O/(±)-CSA afforded 3,3-disubstituted-2,3-dihydroazanaphthoquinones in moderate to excellent yields.