DBU-mediated [4 + 1] annulations of donor-acceptor cyclopropanes with carbon disulfide or thiourea for synthesis of 2-aminothiophene-3-carboxylates.

DBU-mediated [4 + 1] annulations of donor-acceptor cyclopropanes with carbon disulfide or thiourea for synthesis of 2-aminothiophene-3-carboxylates.