Regioselective Synthesis of Functionally Crowded Benzenes at Room Temperature through Ring Transformation of 2H-Pyran-2-ones

An expeditious synthesis of highly substituted benzenes with electron withdrawing or donating substituents is described and illustrated by carbanion-induced ring transformation of 2H-pyran-2-one with malononitrile in excellent yield. The novelty of the reaction lies in the creation of an aromatic ring at room temperature from six membered-lactones under mild reaction conditions.

Regioselective Synthesis of 2-Amino-isophthalonitriles through a Ring Transformation Strategy

An expeditious synthesis of several 2-amino-isophthalonitriles and their biaryl compounds is described and illustrated by carbanion-induced ring transformation of functionalized 2H-pyran-2-ones with malononitrile in excellent yields. The strength of the reaction lies in the creation of an aromatic ring at room temperature from six membered-lactones under mild reaction conditions. This approach is an alternative to Diels-Alder reactions of 2H-pyran-2-ones with dienophiles, which require forcing thermal conditions to obtain benzene derivatives.

Expeditious synthesis of 5,6,7 ,8-tetrahydro-imidazo[1,2-a ] pyrimidin-2-ones and 3,4,6,7 ,8,9-hexahydro-pyrimido[,2-a ] pyrimidin-2-ones

A convenient synthesis of new 5,6,7 ,8-tetrahydro-imidazo[ 1,2-a]pyrimidin-2-ones and 3,4,6,7 ,8,9-hexahydro-pyrimido[1 ,2a]pyrimidin-2- ones from the Baylis-Hillman adducts of acrylonitrile and their derivatives is described. A common strategy employed to achieve the syntheses of title compounds involved generation of diamines from different Baylis-Hillman derivatives followed by treatment with cyanogen bromide at reflux temperature to trigger a double intramolecular cyclization.