Research output: Contribution to journal › Article › peer-review
An efficient two-step procedure "imine formation/azirine-carbenoid coupling" has been developed for the preparation of 1,2-dihydropyrimidines from azirine-2-carbaldehydes, primary amines, and diazo carbonyl compounds under Rh(II) catalysis. The formation of 1,2-dihydropyrimidines involves 100% regioselective addition of the rhodium carbenoid to endocyclic nitrogen atom of the 2H-azirine-2-carbaldimine. According to the DFT calculations the reaction proceeds via dissociation of the metal-bound complex of the azirinium ylide to metal-free azirinium ylide, ring-opening of the latter to give a 1,5-diazahexa-1,3,5-triene, followed by 1,6-cyclization. The 1,2-dihydropyrimidines with two different electron-withdrawing substituents at the C2 position can undergo in solution inversion of configuration of the stereogenic center at C2 via "the N1-C2 bond cleavage/rotation around the N-C single bond/1,6-cyclization" sequence.
Original language | English |
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Pages (from-to) | 13396-13404 |
Number of pages | 9 |
Journal | Journal of Organic Chemistry |
Volume | 82 |
Issue number | 24 |
DOIs | |
State | Published - 15 Dec 2017 |
ID: 13392547