A new method for the reductive coupling of alkynes to enones has been developed. This method provides an alternative to more traditional methods of conjugate addition and provides advances in terms of regioselectivity. Other methods rely on the use of preformed organometallic reagents that must be generated in situ stoichiometrically, while this approach utilizes simpler, more readily available starting materials. This method also offers an improved substrate scope over analogous methodologies.
Pyrroles, furans and thiophenes make up a class of heterocycles that are present in a broad range of biologically active natural products and pharmaceutically relevant molecules. There is a wide variety of methods for their synthesis, and one of the most widely used strategies, the Stetter-Paal-Knorr sequence, relies on access to 1,4-diketones. The reductive coupling of enones and alkynes allows for access to products that, upon oxidative cleavage, can be used as precursors to five-membered heterocycles. This process allows access to a wide variety of diversely substituted and polycyclic products.
The development of regiocontrol for a variety of coupling reactions was examined. Being able to selectively hydroborate or hydrosilylate π-systems such as dienes or alkynes provides access to useful synthetic intermediates. In an attempt to develop regiocontrol for the enone-alkyne reductive coupling, a new reaction was discovered, allowing for the stereoselective synthesis of 1,4-skipped dienes.Ph.D.ChemistryUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/91615/1/benthomp_1.pd
