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Iron-catalyzed urea synthesis: dehydrogenative coupling of methanol and amines.

ABSTRACT: Substituted ureas have numerous applications but their synthesis typically requires the use of highly toxic starting materials. Herein we describe the first base-metal catalyst for the selective synthesis of symmetric ureas via the dehydrogenative coupling of methanol with primary amines. Using a pincer supported iron catalyst, a range of ureas was generated with isolated yields of up to 80% (corresponding to a catalytic turnover of up to 160) and with H₂ as the sole byproduct. Mechanistic studies indicate a stepwise pathway beginning with methanol dehydrogenation to give formaldehyde, which is trapped by amine to afford a formamide. The formamide is then dehydrogenated to produce a transient isocyanate, which reacts with another equivalent of amine to form a urea. These mechanistic insights enabled the development of an iron-catalyzed method for the synthesis of unsymmetric ureas from amides and amines.

SUBMITTER: Lane EM

PROVIDER: S-EPMC5944220 | biostudies-literature | 2018 Apr

REPOSITORIES: biostudies-literature

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Iron-catalyzed urea synthesis: dehydrogenative coupling of methanol and amines.

Lane Elizabeth M EM Hazari Nilay N Bernskoetter Wesley H WH

Chemical science 20180409 16

Substituted ureas have numerous applications but their synthesis typically requires the use of highly toxic starting materials. Herein we describe the first base-metal catalyst for the selective synthesis of symmetric ureas <i>via</i> the dehydrogenative coupling of methanol with primary amines. Using a pincer supported iron catalyst, a range of ureas was generated with isolated yields of up to 80% (corresponding to a catalytic turnover of up to 160) and with H<sub>2</sub> as the sole byproduct. ...[more]

PMID: 29780531

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