in 36-53% yield. The absolute stereochemistry of 3a was assigned unambiguously by single-crystal X-ray diffraction analysis and that of the other derivatives were assigned by analogy (for details see the supporting information). Next, we screened the metals and found that Cu(OTf)2 was still the best (87% yield). In addition to the above, we optimized the solvents(MeOH, PhCF3 and THF) and found that DCM is also the superior one. Furthermore, we screened organic and inorganic bases and found that triethylamine was the best base. With the optimized reaction conditions in hand (Table , entry 16), a variety of ethynyl methylene cyclic carbamates (EMCCs) were employed to test the generality of this process (Scheme 2). Impressively, reactions of EMCCs bearing phenyl groups with various substituents showed good yields whether the substituent was electron-withdrawing (3b-3f) or electrondonating (3g-3i), regardless of its position (para or meta). When R was an alkyl group (i-Pr or Bn), corresponding products 3j and 3l were also obtained in good yields (66-87%). A long alkyl chain bearing an ether group was also suitable, as shown in the formation of 3k. Various amine nucleophiles were then examined (Scheme 3). The use of aryl amines bearing electron-donating groups afforded the polysubstituted pyrroles in good yields (4b-4f; 43-78% ). Besides, the aryl amines equipped with strongly electron with-drawing substituents such as F, CF3, -SCF3, and -OCF2H gave rise to products 4g-4l with 62-76% yields under the optimized conditions. Furthermore, when there are weak substituents on the benzene ring of aromatic amines, such as Cl, Br and I, better yields can be achieved (4m-4o; 68-73%). On the contrary, when there are strong substituents on the benzene ring of aromatic amines, such as ester groups or compounds with cyanide groups, general yields can be achieved (4p-4r; 47-65%). In order to further explore the influence of amine structure on the reaction (Scheme 4), we introduced cycloalkanes on the benzene ring, which can achieve good yields. However, when the amine structure contains oxygen heterocycles, the yield decreases.