title: Ruthenium-porphyrin-catalyzed diastereoselective intramolecular alkyl carbene insertion into C-H bonds of alkyl diazomethanes generated in situ from N-tosylhydrazones.
abstract: With a ruthenium-porphyrin catalyst, alkyl diazomethanes generated in situ from N-tosylhydrazones efficiently underwent intramolecular C(sp(3))-H insertion of an alkyl carbene to give substituted tetrahydrofurans and pyrrolidines in up to 99% yield and with up to 99:1 cis selectivity. The reaction displays good tolerance of many functionalities, and the procedure is simple without the need for slow addition with a syringe pump. From a synthetic point of view, the C-H insertion of N-tosylhydrazones can be viewed as reductive coupling between a C=O bond and a C-H bond to form a new C-C bond, since N-tosylhydrazones can be readily prepared from carbonyl compounds. This reaction was successfully applied in a concise synthesis of (±)-pseudoheliotridane.
authors.affiliation: HKU Shenzhen Institute of Research and Innovation, Shenzhen (China); State Key Laboratory of Synthetic Chemistry and Department of Chemistry, The University of Hong Kong, Hong Kong (China).
authors.forename: Annapureddy Rajasekar
authors.initials: AR
authors.lastname: Reddy
authors.forename: Cong-Ying
authors.initials: CY
authors.lastname: Zhou
authors.forename: Zhen
authors.initials: Z
authors.lastname: Guo
authors.forename: Jinhu
authors.initials: J
authors.lastname: Wei
authors.forename: Chi-Ming
authors.initials: CM
authors.lastname: Che
keywords: CH insertion; alkyl carbenes; alkyl diazomethanes; homogeneous catalysis; ruthenium