Scalable Synthesis of Piperazines Enabled by Visible‐Light Irradiation and Aluminum Organometallics

Abstract

The development of more active CÀHo xidation catalysts has inspired ar apid, scalable,a nd stereoselective assembly of multifunctional piperazines through a[ 3 + +3] coupling of azomethine ylides.Acombination of visible-light irradiation and aluminum organometallics is essential to promote this transformation, which introduces visible-light photochemistry of main-group organometallics and sets the basis for new and promising catalysts.

The medicinal chemistry of piperazines: A review

“…In 2015, Mendoza with his colleagues reported a dimerization reaction of azomethine ylides for piperazine synthesis. In this reaction azomethine ylides (64) are converted into desired derivatives of piperazine 66(a‐c) when reacted with trimethylaluminum (65) in the presence of white LED lamps, and tetrahydrofuran (THF) has been used as a solvent (Scheme 20) (Suárez‐Pantiga et al., 2015). The piperazines that have been produced are in excellent yield, high stereoselectivity, and in gram scale.…”

“…into desired derivatives of piperazine 66(a-c) when reacted with trimethylaluminum (65) in the presence of white LED lamps, and tetrahydrofuran (THF) has been used as a solvent (Scheme 20) (Suárez-Pantiga et al, 2015). The piperazines that have been produced are in excellent yield, high stereoselectivity, and in gram scale.…”

Direct and Stereospecific [3+2] Synthesis of Pyrrolidines from Simple Unactivated Alkenes

“…[1] In this sense,stereodefined polydentate N-donor ligands are particularly demanding owing to their nucleophilicity,redox chemistry,and strong binding to transition metals. [1] In this sense,stereodefined polydentate N-donor ligands are particularly demanding owing to their nucleophilicity,redox chemistry,and strong binding to transition metals.…”

“…The discovery of catalysts to enable new,more efficient, and more sustainable transformations is ap rime objective of our time.T ot his end, the development of new transition-metal catalysts requires new synthetic methods that can quickly supply diverse and powerful ligands.R ecent research targeting ligand synthesis has enabled practical access to important catalysts and contributed solutions to fundamental synthetic challenges. [1] In this sense,stereodefined polydentate N-donor ligands are particularly demanding owing to their nucleophilicity,redox chemistry,and strong binding to transition metals. Unlike the common syntheses based on C À Nb ond-forming reactions, [2] our group has recently reported an alternative approach based on C À Cb ond construction.…”