1. Cheng-Xia Miao, Liang-Nian He,* Jin-Quan Wang, Jian Gao, Biomimetic Oxidation of Alcohol Catalyzed by TEMPO-Functionalized Polyethylene Glycol and Copper(I) Chloride in Compressed Carbon Dioxide, Synlett, 2009, (20), 3291-3294. [link]

Abstract: Recyclable TEMPO-functionalized polyethylene glycol [PEG₆₀₀₀-(TEMPO)₂] in combination with cuprous chloride were developed for biomimetic oxidation of a series of benzylic, allylic, heterocyclic alcohols and 2-phenylethanol into the corresponding aldehydes or ketones with high selectivity and moderate to high conversion in the environmentally friendly and safe medium, i.e. compressed CO₂, which enhanced the catalytic activity as well as improved the selectivity.

2. C.-X. Miao, L.-N. He,* J.-Q. Wang, J.-L.Wang, TEMPO and Carboxylic Acid Functionalized Imidazolium Salts/NaNO₂: An Efficient, Reusable, Transition Metal-Free Catalytic System for Aerobic Oxidation of Alcohol, Adv. Synth. Catal., 2009, 351(13), 2209-2216. [link]

Abstract: An effective catalytic system comprising a TEMPO functionalized ionic liquid (IL-TEMPO), a carboxylic acid substituted imidazolium-based ionic liquid (IL-COOH), and NaNO₂ was deveolped for aerobic oxidation of aliphatic, allylic, heterocyclic and benzylic alcohols to the respective carbonyl compounds with excellent selectivity up to >99 %, even at ambient condition. Notably, the catalyst system could preferentially oxidize a primary alcohol to the aldehyde rather than a secondary alcohol. Moreover, the reaction rate is greatly enhanced with proper amount of water present. And a high turnover number  (TON 5 000) is achieved in the present transition-metal-free aerobic catalytic system. Additionally, the functionalized ionic liquids are successfully reused at least four times. This process thus represents a greener pathway for aerobic oxidation of alcohols into carbonyl compounds by using the present task-specific ionic liquids in place of the toxic and volatile additive, such as HBr, Br₂, HCl, which is commonly required for the transition-metal-free aerobic oxidation of alcohols.

3. J.-L. Wang, L.-N. He,* C.-X. Miao, Y.-N. Li, Ethylene carbonate as a unique solvent for palladium-catalyzed Wacker oxidation using oxygen as the sole oxidant, Green Chem., 2009, 11, 1317-1320. (Top 10 for November 2009)[link]

Abstract: Ethylene carbonate as a unique solvent for Wacker oxidation of higher alkenes and aryl alkenes has been successfully developed using molecule oxygen as the sole oxidant, in which the colloidal Pd nanoparticles stabilized in EC is considered to facilitate its reoxidation under cocatalyst-free conditions.

4. J.-Q. Wang, L.-N. He,* Polyethylene Glycol radical-initiated benzylic C-H bond oxygenation in compressed carbon dioxide, New J. Chem., 2009, 33(8), 1637-1640. [link]

Abstract: A new methodology to induce free radical reactions was established by the oxygenation of benzylic hydrocarbons in dense CO₂. The PEG radical originating from thermal/oxidative degradation of PEG in dense CO₂ was successfully applied to the oxygenation of benzylic hydrocarbons with enormous synthetic potentials under organic solvent-free conditions. In addition, the dense CO₂ in our study could improve the oxygenation reaction.

5. 何良年，王金泉，窦晓勇. 离子液体与绿色化学 3.1 离子液体与二氧化碳的化学转化利用，(21世纪科学版化学专著系列，ISBN 978-7-03-024616-5)北京：科学出版社，2009年5月第一版，p.249-275. (Book review invited by editor)

6. J.-Q. Wang, L.-N. He,* C.-X. Miao, J. Gao, The Free-Radical Chemistry of Polyethylene Glycol: Organic Reaction in Compressed Carbon Dioxide, ChemSusChem, 2009, 2, 755-760. (most accessed article in 02/2010)[link]

Abstract: The thermal/oxidative degradation of polyethylene glycol (PEG) is known to occur under oxygen atmosphere at elevated temperature. In conjunction with compressed CO₂, PEG radical assumed to be generated from PEG thermal oxidative degradation was first successfully applied to initiate a set of free radical reactions such as selective formylation of primary and secondary aliphatic alcohols, and oxidation of benzylic alcohols, and benzylic C=C bond cleavage and benzylic sp³ C-H oxidation with enormous synthetic potentials in a practically utilizable manner with cost-efficient and environmentally friendly benefit without any additional free radical initiator nor a catalyst. We find that both PEG and molecule oxygen are prerequisite to performing those reactions smoothly. Given that dense CO₂ is immune to free radical chemistry; it is an ideal solvent for such free radical reactions. As a result, compressed CO₂ in this elegant study allows such reactions initiated by PEG radical able to be tuned by subtly adjusting reaction parameter like CO₂ pressure, thus leading to enhancing the product selectivity. Attaining high selectivity towards the desired product makes this methodology more practical in organic synthesis.

7. Y. Wu, L.-N. He*, Y. Du, J.-Q. Wang, C.-X. Miao, Zirconyl chloride: an efficient recyclable catalyst for  synthesis of 5-aryl-2-oxazolidinones CO₂ under solvent-free conditions, Tetrahedron, 2009, 65(31), 6204-6210. [link] 

Abstract: The cycloaddition reaction of aziridines with CO₂ heterogeneously catalyzed by ZrOCl₂.8H₂O smoothly proceeded, leading to the preferential formation of 5-aryl-2-oxazolidinones; and excellent yields, regio- and stereoselectivities towards the target products were reached under solvent-free conditions.

8. Jin-Quan Wang, Liang-Nian He* and Cheng-Xia Miao, Polyethylene glycol radical-initiated oxidation of benzylic alcohols in compressed carbon dioxide, Green Chem. 2009, 11, 1013-1017.[link]

Abstract: The PEG radical from oxidative degradation of polyethylene glycol was first used to initiate the oxidation of benzylic alcohols to carbonyl compounds without the need of a catalyst and additive in a viable synthetic, cost-effective and environmentally benign way, in which PEG/O₂/CO₂ acts as initiator, oxidant and solvent.

9. Jing-Lun Wang, Liang-Nian He,* Xiao-Yong Dou, Fang Wu, Polyethylene glycol: an alternative solvent for the synthesis of cyclic carbonate from vicinal halohydrin and carbon dioxide, Aus. J. Chem., 2009, 62, 917-920. [link]

10. L.-N. He*, J.-Q. Wang, J.-L. Wang, Carbon dioxide chemistry: examples and challenges in chemical utilization of carbon dioxide, Pure Appl. Chem. 2009, 81(11), 2069-2080. (invited by editor)[link]

11. L.-N. He*, Y. Du, C.-X. Miao, J.-Q. Wang, X.-Y. Dou, Y. Wu, Methodologies for chemical utilization of CO₂ to valuable compounds through molecular activation by efficient catalysts, Front. Chem. Eng. China, 2009, 3(2), 224-228.

12. 汪靖伦，何良年*，王金泉，杜亚，苗成霞，窦晓勇，吴颖，高健, 温室气体二氧化碳化学转化与利用的方法学,精细化工中间体, 2009, 39 (5), 1-7. (invited by editor) [link]