Synthesis of Pyrroles via Consecutive 6π-Electrocyclization/Ring-Contraction of Sulfilimines
作者:Franz-Lucas Haut、Niklas J. Feichtinger、Immanuel Plangger、Lukas A. Wein、Mira Müller、Tim-Niclas Streit、Klaus Wurst、Maren Podewitz、Thomas Magauer
DOI:10.1021/jacs.1c04835
日期:2021.6.23
We present a modular, synthetic entry to polysubstituted pyrroles employing readily available 2,5-dihydrothiophenes. Ring-opening of the heterocycle provides access to a panel of 1,3-dienes which undergo pyrrole formation in the presence of inexpensive chloramine-T trihydrate. The transformation is conducted in an open flask and proceeds at ambient temperatures (23 °C) in nondry solvents. A careful
Several 3,4-disubstituted 3-sulfolenes 1aâj, the precursors for the corresponding 2,3-disubstituted 1,3-dienes 2aâj, are conveniently prepared and undergo DielsâAlder reactions smoothly with methyl acrylate under thermal conditions where the order of para-directing ability of different substituents is OTBSâCN > SPh > OMeâCO2Me > OTs > OAc.