有效地实现了布朗斯台德酸介导的内烯烃α-氧代乙烯酮二硫缩醛与吡咯的环化反应,得到环戊[ b ]吡咯。一对具有酸强度的布朗斯台德酸,即三氟乙酸和对甲苯磺酸水合物,被用于促进环化反应。生成的产物很容易被间氯过氧苯甲酸氧化成砜。随后用1,8-二氮杂双环[5.4.0]十一碳-7-烯处理得到脱硫的烯烃中间体脱硫的末端烯烃或[2 + 2]环加成产物。本协议提供了在温和条件下易于访问结构多样的环戊[ b ]吡咯衍生物的方法。
Brønsted Acid-Promoted Cascade Alkylation/Cyclization of Pyrroles with<i>N</i>,<i>N</i>-Dimethylaminomethyleneglutaconic Acid Dinitrile: A Concise Route to Cyclopenta[<i>b</i>]pyrroles
A Brønstedacid (p-TsOH⋅H2O) promoted alkylation/cyclizationcascade reaction of pyrroles with N,N-dimethylaminomethyleneglutaconicaciddinitrile was efficiently realized to afford functionalized cyclopenta[b]pyrroles with excellent diastereoselectivity. Deamination of the corresponding ammonium salts of the cyclopenta[b]pyrroles with methyl iodide led to dihydrocyclopenta[c]pyrroles. The cascade reaction
有效地实现了布朗斯台德酸(p -TsOH·H 2 O)促进吡咯与N,N-二甲基氨基亚甲基戊二酸二腈的烷基化/环化级联反应,从而提供具有优异非对映选择性的官能化环戊[ b ]吡咯。环戊[ b ]吡咯的相应铵盐与甲基碘的脱氨基反应生成二氢环戊[ c ]吡咯。通过反应中间体,即2-烷基化吡咯的分离和转化,证实了级联反应途径。
Cobalt‐Mediated Photochemical C−H Arylation of Pyrroles
作者:Julia Märsch、Sebastian Reiter、Thomas Rittner、Rafael E. Rodriguez‐Lugo、Maximilian Whitfield、Daniel J. Scott、Roger Jan Kutta、Patrick Nuernberger、Regina de Vivie‐Riedle、Robert Wolf
DOI:10.1002/anie.202405780
日期:2024.7.8
An octahedrally coordinated bis(diiminopyridine)cobalt complex enables the visible-light-driven arylation of pyrroles with chloro- and bromoarenes. Spectroscopic and computational studies elucidate the photoelectron transfer processes of the metal complex with triethylamine and a bromoarene, suggesting that electron transfer is facilitated by a preassembly of these molecules with the complex.