Highly selective carboxylative cyclization of allenylmethylamines with carbon dioxide using N-heterocyclic carbene-silver(I) catalysts

Kyohei Yamashita; Shun Hase; Yoshihito Kayaki; Takao Ikariya

doi:10.1021/acs.orglett.5b00809

Highly selective carboxylative cyclization of allenylmethylamines with carbon dioxide using N-heterocyclic carbene-silver(I) catalysts

Org Lett. 2015 May 15;17(10):2334-7. doi: 10.1021/acs.orglett.5b00809. Epub 2015 Apr 28.

Authors

Kyohei Yamashita¹, Shun Hase¹, Yoshihito Kayaki¹, Takao Ikariya¹

Affiliation

¹ Department of Applied Chemistry, Graduate School of Science and Engineering, Tokyo Institute of Technology, O-okayama 2-12-1-E4-1, Meguro-ku, Tokyo 152-8552, Japan.

PMID: 25918943
DOI: 10.1021/acs.orglett.5b00809

Abstract

Silver(I) carboxylate complexes promote the carboxylative cyclization of allenylmethylamines to afford 5-alkenyl-1,3-oxazolidin-2-ones in 2-propanol. The use of an N-heterocyclic carbene ligand (IPr) under pressurized CO2 is effective in suppressing the intramolecular hydroamination that leads to 2,5-dihydropyrroles. The mechanism involving a nucleophilic attack of the carbamate of the allene moiety and a subsequent protonation was realized on the basis of experimental and theoretical results involving a model intermediate, the alkenylgold(I) complex, which was synthesized from Au(OH)(IPr) and 1-methylamino-2,3-butadiene.