Palladium-Catalyzed Regioselective [5 + 1] Annulation of Vinyl Aziridines/Epoxides with ClCF₂COONa

Abstract

Scheme 1. [Pd II ]CF 2 -Involved Transfer Reactions Letter pubs.acs.org/OrgLett

Recent updates on vinyl cyclopropanes, aziridines and oxiranes: access to heterocyclic scaffolds

“…66 Scheme 27 Synthesis of α,β-unsaturated-δ-lactams and lactones by Li's approach. 65 [3 + 3] cycloaddition reaction to accomplish an array of bi-and tri-heterocyclic scaffolds 83, 84-86 in a moderate yield (up to 73%). In this strategy, not all the aldehydes were successful in the cycloannulation reaction.…”

“…Zhang's group 63 and Song's group 64 utilized difluorocarbene reagents for fluoroalkylations via a Pd( ii )–CF 2 H intermediate and fluorination via Pd( ii )CF 2 in the presence of H 2 O to release a CO source for a [4 + 1] annulation reaction. In addition to reports in the literature, Li and co-workers 65 recently reported the Pd-catalyzed synthesis of δ-lactams by utilizing vinyl aziridines 56 with ClCF 3 CO 2 Na 76 as a carbonyl source in a [5 + 1] cycloaddition reaction (Scheme 27). The initial study showed that the success of [5 + 1] cycloaddition relies on the presence of Pd(OAc) 2 , PCy 3 , and K 2 CO 3 in dry DMF.…”

Recent advances in the accessibility, synthetic utility, and biological applications of aziridines

“…The authors reported a difluorocarbene-involved (161) reaction of π-allyl Pd(II) complexes (Scheme 30path a). 54 In 2023, Song et al synthesized chiral γ-lactams (167) through an isothiourea (166, ITU)/iridium (164) co-catalyzed reaction of vinyl aziridines (163) with pentafluorophenyl esters (162). This methodology allowed the achievement of several optically active compounds in good yields and with high asymmetric induction (up to 98% ee) (Scheme 30path b).…”

“…The authors reported a difluorocarbene-involved ( 161 ) reaction of π-allyl Pd( ii ) complexes (Scheme 30 – path a). 54…”

Palladium-Catalyzed Iodine Assisted Carbonylation of Indoles with ClCF2CO2Na and Alcohols

“…8 Song's group developed an elegant Pd-catalyzed [4 + 1] annulation of 2-iodobiphenyls with ClCF 2 CO 2 Na. 9 Additionally, we disclosed a Pd-catalyzed regioselective [5 + 1] annulation of vinyl aziridines/epoxides with ClCF 2 COONa. 10 Inspired by employing difluorocarbene as carbonyl source 8−10 and the preiodination strategy of indoles, 5b we herein developed a practical and efficient Pd-catalyzed, iodine-assisted carbonylation of indoles using ClCF 2 CO 2 Na and alcohols.…”