On the Most Powerful Chemical Traps for Bis(methoxycarbonyl)carbene (=2-Methoxy-1-(methoxycarbonyl)-2-oxoethylidene)
✍ Scribed by Vladimir V. Shevchenko; Natalya G. Zhegalova; Andey O. Borzenko; Valerij A. Nikolaev
- Book ID
- 102258731
- Publisher
- John Wiley and Sons
- Year
- 2008
- Tongue
- German
- Weight
- 205 KB
- Volume
- 91
- Category
- Article
- ISSN
- 0018-019X
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✦ Synopsis
Abstract
The efficiency and validity of different chemical substrates for trapping bis(methoxycarbonyl)carbene (=2‐methoxy‐1‐(methoxycarbonyl)‐2‐oxoethylidene; 1) is dependent on the conditions of carbene generation. On conventional photolysis of dimethyldiazomalonate (=2‐diazopropanedioic acid dimethyl ester; 2) by long‐wave UV light (through a Pyrex filter, λ>290 nm), the most powerful trap for carbene 1 in the series of substrates Me~2~S, MeOH, cyclohexane, and pyridine is Me~2~S (with an efficiency ratio of ca. 6 : 4 : 2 : 1, resp.). When short‐wave decomposition of diazomalonate 2 is employed (through a quartz filter, λ>210 nm), more reliable and useful chemical traps for bis(methoxycarbonyl)carbene (1) are pyridine and cyclohexane, whose adducts with 1 are rather stable under short‐wave‐irradiation conditions. Application of alcohols for the trapping of 1 proves to be preferential when simultaneous monitoring of carbene and oxoketene formation during photolysis is necessary.