Chemical fixation of CO 2 /CS 2 to access iodoallenyl oxazolidinones and allenyl thiazolidine-thiones

Constructing heterocyclic compounds by chemical fixation of CO /CS as a C1 building block is a promising approach. An efficient and environmentally friendly synthetic approach has been developed using CO /CS to prepare complicated allenyl heterocycles with high yields and diastereoselectivities in a metal-free manner under mild conditions. NIS promoted CO fixation and the cyclization reaction by exclusive 1,4- -addition of 1,3-enynes rather than 1,2-addition or 3,4-addition, while CS participated in unique 1,4- -hydrothiolation of 1,3-enynes to afford allenyl heterocycles with different reaction patterns.