title: Direct Synthesis of Symmetrical Azines from Alcohols and Hydrazine Catalyzed by a Ruthenium Pincer Complex: Effect of Hydrogen Bonding.
abstract: Azines (2,3-diazabuta-1,3-dienes) are a widely used class of compounds with conjugated C=N double bonds. Herein, we present a direct synthesis of azines from alcohols and hydrazine hydrate. The reaction, catalyzed by a ruthenium pincer complex, evolves dihydrogen and can be run in a base-free version. The dehydrogenative coupling of benzylic and aliphatic alcohols led to good conversions and yields. Spectroscopic evidence for a hydrazine-coordinated dearomatized ruthenium pincer complex was obtained. Isolation of a supramolecular crystalline compound provided evidence for the important role of hydrogen bonding networks under the reaction conditions.
authors.affiliation: Department of Organic Chemistry and Department of Chemical Research Support, The Weizmann Institute of Science , 76100 Rehovot, Israel.
authors.forename: Jonathan O
authors.initials: JO
authors.lastname: Bauer
authors.affiliation: Department of Organic Chemistry and Department of Chemical Research Support, The Weizmann Institute of Science , 76100 Rehovot, Israel.
authors.forename: Gregory
authors.initials: G
authors.lastname: Leitus
authors.affiliation: Department of Organic Chemistry and Department of Chemical Research Support, The Weizmann Institute of Science , 76100 Rehovot, Israel.
authors.forename: Yehoshoa
authors.initials: Y
authors.lastname: Ben-David
authors.affiliation: Department of Organic Chemistry and Department of Chemical Research Support, The Weizmann Institute of Science , 76100 Rehovot, Israel.
authors.forename: David
authors.initials: D
authors.lastname: Milstein
keywords: azines; homogeneous catalysis; hydrogen bonds; pincer complexes; ruthenium; supramolecular compounds