title: Synthesis of aromatic aza-metallapentalenes from metallabenzene via sequential ring contraction/annulation.
abstract: The concept of aromaticity has long played an important role in chemistry and continues to fascinate both experimentalists and theoreticians. Among the archetypal aromatic compounds, heteroaromatics are particularly attractive. Recently, substitution of a transition-metal fragment for a carbon atom in the anti-aromatic hydrocarbon pentalene has led to the new heteroaromatic osmapentalenes. However, construction of the aza-homolog of osmapentalenes cannot be accomplished by a similar synthetic manipulation. Here, we report the synthesis of aza-osmapentalenes by sequential ring contraction/annulation reactions of osmabenzenes via osmapentafulvenes. Nuclear magnetic resonance spectra, X-ray crystallographic analysis, and DFT calculations all suggest that these aza-osmapentalenes exhibit aromatic character. Thus, the stepwise transformation of metallabenzenes to metallapentafulvenes and then aza-metallapentalenes provides an efficient and facile synthetic route to these bicyclic heteroaromatics.
authors: State Key Laboratory of Physical Chemistry of Solid Surfaces and Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), and Department of Chemistry, Xiamen University, Xiamen 361005, China.
authors: Tongdao
authors: T
authors: Wang
authors: State Key Laboratory of Physical Chemistry of Solid Surfaces and Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), and Department of Chemistry, Xiamen University, Xiamen 361005, China.
authors: Feifei
authors: F
authors: Han
authors: State Key Laboratory of Physical Chemistry of Solid Surfaces and Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), and Department of Chemistry, Xiamen University, Xiamen 361005, China.
authors: Haiping
authors: H
authors: Huang
authors: State Key Laboratory of Physical Chemistry of Solid Surfaces and Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), and Department of Chemistry, Xiamen University, Xiamen 361005, China.
authors: Jinhua
authors: J
authors: Li
authors: 1] State Key Laboratory of Physical Chemistry of Solid Surfaces and Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), and Department of Chemistry, Xiamen University, Xiamen 361005, China [2] Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong.
authors: Hong
authors: H
authors: Zhang
authors: State Key Laboratory of Physical Chemistry of Solid Surfaces and Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), and Department of Chemistry, Xiamen University, Xiamen 361005, China.
authors: Jun
authors: J
authors: Zhu
authors: Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong.
authors: Zhenyang
authors: Z
authors: Lin
authors: State Key Laboratory of Physical Chemistry of Solid Surfaces and Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), and Department of Chemistry, Xiamen University, Xiamen 361005, China.
authors: Haiping
authors: H
authors: Xia