Our major objectives for the second year of the grant will be to delineate the scope and limitations of our recently documented inter- and intramolecular (4+2)-cycloaddition of nitroalkenes with unactivated olefins. Our initial studies have demonstrated a high degree of stereocontrol in the formation of six-membered rings. We intend to address the flexibility of the reaction in creation of four, five, seven and eight-membered rings by intramolecular cycloaddition. We propose to investigate-the incorporation of stereocenters and heteroatoms in the connecting chain between heterodiene and dienophile as well as on the heterodiene itself. The synthesis and utilization of nitrocycloalkenes of various sizes and degrees of functionalization is also planned. A second major objective is the demonstration of the tandem double- intramolecular (4+2) + (3+2)-cycloaddition originally proposed. We have demonstrated the feasibility of this reaction in the intra/intermolecular mode and will explore the parameters of second chain length and dipolarophilic activating group. Secondary goals include manipulation of the double cycloadducts and the products of (4+2)-cycloaddition from vinylnitrosonium cations. We have recently completed a successful study on the potential for transformations of the cyclic nitronates from cycloadditions of nitroolefins. Reductive, hydrolytic and carbon constructive processes are proposed for the unusual, saturated heterocyclic products. A tertiary goal is the exploration of the anion chemistry of nitronic esters and nitroalkenes. These highly oxidized functions should offer novel avenues for carbon-carbon bond formation due to their strong acidifying effects. The problems of regioselectivity, stereoselectivity and reactivity will be addressed.
Showing the most recent 10 out of 35 publications
