Synthesis of Nitrogen Heterocycles via Photochemical Ring Opening of Pyridazine N-Oxides.

A photochemical method for the direct synthesis of 1H-pyrazoles from pyridazine N-oxides was developed. This chemistry features a regioselective approach to nonsymmetrically substituted pyridazine N-oxides. Herein, we highlight the first strategic use of photoinduced ring-opening reactions of 1,2-diazine N-oxides for the preparative synthesis of nitrogen heterocycles.

A Scalable Protocol for the Regioselective Alkylation of 2-Methylcyclohexane-1,3-dione with Unactivated sp Electrophiles.

A method for the C-selective alkylation of 2-methylcyclohexane-1,3-dione with unactivated sp electrophiles is accomplished via alkylation and subsequent deprotection of the derived ketodimethyl hydrazones. The present method provides a high-yielding entry to dialkyl cycloalkanones that cannot be accessed via direct alkylation of 2-methylcyclohexane-1,3-dione. The title reaction may be useful in the scalable preparation of terpene and steroidal building blocks in the arena of natural product synthesis.