Regioselective Alkenylation of Five-Membered Heteroarenes via a Dual 1,3-Sulfur Rearrangement.

Herein, we report a protocol for the stereoselective C-H alkenylation of five-membered heteroarenes including pyrroles (containing free NH pyrrole), thiophenes, and furans with 1,3-dithiane derivatives through dual 1,3-sulfur rearrangements. The site-selective and regioselective alkenylation of the five-membered heteroarenes proceeded in good yields via vinyl thionium ions to produce C2 or C5 Heck-type products, respectively.