Construction of polysubstituted spiro[2.3] or [3.3] cyclic frameworks fused with a tosylated pyrrolidine promoted by visible-light-induced photosensitization

Abstract

A novel visible-light-induced intramolecular [2 + 2] cycloaddition of methylenecyclopropanes (MCPs) for the rapid construction of polysubstituted spiro[2.3] or [3.3] cyclic frameworks fused with a tosylated pyrrolidine.

Visible-light-induced reactions of methylenecyclopropanes (MCPs)

“…In 2021, our group reported a visible-light-induced intramolecular [2+2] cycloaddition of MCPs 114 for the construction of polysubstituted cyclic frameworks 115 (Scheme 23). 59 In this reaction, the triplet excited state 117 is produced through energy transfer (EnT) between…”

“…In 2021, our group reported a visible-light-induced intramolecular [2+2] cycloaddition of MCPs 114 for the construction of polysubstituted cyclic frameworks 115 (Scheme 23). 59 In this reaction, the triplet excited state 117 is produced through energy transfer (EnT) between the excited state of *Ir( iii ) and 116 , in addition to subsequent intersystem crossing (ISC). Intermediate 117 undergoes intramolecular C–C bond formation with a closed-shell carbon–carbon double bond, yielding the 1,4-triplet biradical species 118 .…”

Dearomative intermolecular [2 + 2] photocycloaddition for construction of C(sp3)-rich heterospirocycles on-DNA

“…[5][6][7][8][9] Syntheses of spiro [3.3]heptanes have been mostly achieved via photochemical [2+2] cycloaddition. [10][11][12] However, to our knowledge, a general method for the preparation of diverse spiro [3.3]heptanes on-DNA has yet to be reported. DNA-encoded chemical library (DEL) technology has emerged as a powerful tool for hit identification in modern drug discovery.…”

“…[5][6][7][8][9] Syntheses of spiro [3.3] heptanes have been mostly achieved via photochemical [2 + 2] cycloaddition. [10][11][12] However, to our knowledge, a general method for the preparation of diverse spiro [3.3]heptanes on-DNA has yet to be reported.…”