An Unusual Iron-Dependent Oxidative Deformylation Reaction Providing Insight into Hydrocarbon Biosynthesis in Nature
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- 作者：Benjamin R. Ellington ; Bishwajit Paul ; Debasis Das ; Andrew K. Vitek ; Paul M. Zimmerman ; E. Neil G. Marsh
- 刊名：ACS Catalysis
- 出版年：2016
- 出版时间：May 6, 2016
- 年：2016
- 卷：6
- 期：5
- 页码：3293-3300
- 全文大小：406K
- 年卷期：0
- ISSN：2155-5435
文摘
The development of new pathways for next-generation biofuel production has spurred recent investigations into the mechanisms of enzymes that biosynthesize hydrocarbons. One widely distributed group of enzymes, aldehyde decarbonylases, catalyze unusual deformylation reactions in which long-chain fatty aldehydes are converted to alkanes. These enzymes are all iron-dependent and in insects are represented by a cytochrome P450 enzyme that releases the aldehyde carbon as CO2. Here we describe a novel nonenzymatic reaction of an α-cyclopropyl-substituted aldehyde that mimics the enzyme reaction. This aldehyde is oxidatively deformylated in the presence of aqueous iron(II) salts and oxygen to yield an alkyl-substituted cyclopropane and CO2, in a reaction that competes with the more conventional oxidation of the aldehyde to the carboxylic acid. Like the enzymatic reaction, the reaction occurs with retention of the aldehyde proton in the alkane product and probably proceeds through an iron–peroxo species. Computational reaction discovery tools were used to search for potential reaction pathways and investigate their energetic feasibility. These identified a plausible reaction pathway leading to the experimentally observed products and reproduced the transfer of the aldehyde proton to the cyclopropane product. These studies provide further insight into how enzymes may control reactive iron–oxo species to catalyze the diverse range of iron-dependent oxidative transformations observed in biology.