1,3-Dipolar cycloaddition reactions of ylides formed from pyridines and dichlorocarbene

Competition between [2 + 1]- and [4 + 1]-cycloaddition mechanisms in reactions of conjugated nitroalkenes with dichlorocarbene in the light of a DFT computational study

“…In particular, we decided to shed light on the molecular mechanism of model transformations involving a representative series of conjugated nitroalkenes (1ae) and dichlorocarbene (2) (Scheme 1). Carbene 2 is well known and may be easily generated in the reaction environment [22][23][24][25]. On the other hand, five nitroalkenes (1ae) characterized by a different type of substitution were selected.…”

Pyrrolizidine and Indolizidine Syntheses Involving 1,3-Dipolar Cycloadditions

“…Pyridinium N-ylides are the most easily available cyclic azomethine ylides. However, their cycloaddition to acetylenes (or to synthetic equivalents of the latter) originates aromatic indolizidines, [85][86][87][88][89][90][91][92][93][94][95][96][97][98][99] which do not reflect exactly the structure of indolizidine alkaloids. More challenging…”

Formation and reactivity of gem-difluoro-substituted pyridinium ylides: Experimental and DFT investigation

“…Ylides, generated by addition of dichlorocarbene to azines, diazines and its fused derivatives, are well studied [8][9][10][11][12][13][14][15]. These species have been used as synthetic blocks in the preparation of chlorosubstituted indolizines, its heteroatomic and fused derivatives via 1,3-dipolar cycloaddition to various dipolarophiles.…”