152171-20-5Relevant academic research and scientific papers
C3-Alkenylation between Pyrroles and Aldehydes Mediated by a Br?nsted Acid and a Br?nsted Base
Sahu, Samrat,Roy, Avijit,Gorai, Mahadeb,Guria, Sudip,Sudan Maji, Modhu
, p. 6396 - 6400 (2019)
A transition-metal-free, redox-neutral, organocatalytic C3-alkenylation of pyrroles is reported. Readily available aldehydes were employed as alkenylating agent and the reaction tolerates several key functional groups. The E-alkenylated products were isolated in moderate to exclusive selectivity. A one-pot two-fold alkenylation strategy is also developed for further downstream modifications. To show the applicability, synthetically challenging indolylpyrrole derivatives were synthesized using Cadogan cyclization.
Metal-Free Directed C?H Borylation of Pyrroles
Wang, Zheng-Jun,Chen, Xiangyang,Wu, Lei,Wong, Jonathan J.,Liang, Yong,Zhao, Yue,Houk, Kendall N.,Shi, Zhuangzhi
, p. 8500 - 8504 (2021/03/16)
Robust strategies to enable the rapid construction of complex organoboronates in selective, practical, low-cost, and environmentally friendly modes remain conspicuously underdeveloped. Here, we develop a general strategy for the site-selective C?H borylation of pyrroles by using only BBr3 directed by pivaloyl groups, avoiding the use of any metal. The site-selectivity is generally dominated by chelation and electronic effects, thus forming diverse C2-borylated pyrroles against the steric effect. The formed products can readily engage in downstream transformations, enabling a step-economic process to access drugs such as Lipitor. DFT calculations (wB97X-D) demonstrate the preferred positional selectivity of this reaction.
