Diazomethane umpolung atop anthracene: An electrophilic methylene transfer reagent
Author(s)Joost, Maximilian; Transue, Wesley J.; Cummins, Christopher C.
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Formal addition of diazomethane's terminal nitrogen atom to the 9,10-positions of anthracene yields H[subscript 2]CN[subscript 2]A (1, A = C[subscript 14]H[subscript 10] or anthracene). The synthesis of this hydrazone is reported from Carpino's hydrazine H[subscript 2]N[subscript 2]A through treatment with paraformaldehyde. Compound 1 has been found to be an easy-to-handle solid that does not exhibit dangerous heat or shock sensitivity. Effective umpolung of the diazomethane unit imbues 1 with electrophilicity at the methylene carbon center. Its reactivity with nucleophiles such as H[subscript 2]CPPh[subscript 3] and N-heterocyclic carbenes is exploited for CC bond formation with elimination of dinitrogen and anthracene. Similarly, 1 is demonstrated to deliver methylene to a nucleophilic singlet d[superscript 2] transition metal center, W(ODipp)[subscript 4] (2), to generate the robust methylidene complex [2=CH[subscript 2]]. This behavior is contrasted with that of the Wittig reagent H[subscript 2]CPPh[subscript 3], a more traditional and Brønsted basic methylene source that upon exposure to 2 contrastingly forms the methylidyne salt [MePPh[subscript 3]][2≡CH].]
DepartmentMassachusetts Institute of Technology. Department of Chemistry
Royal Society of Chemistry (RSC)
Joost, Maximilian, et al. “Diazomethane Umpolung atop Anthracene: An Electrophilic Methylene Transfer Reagent.” Chemical Science 9, 6 (2018): 1540–43. © 2018 The Royal Society of Chemistry
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