Lewis Acid Catalyzed Nucleophilic Ring Opening and 1,3-Bisfunctionalization of Donor–Acceptor Cyclopropanes with Hydroperoxides: Access to Highly Functionalized Peroxy/(α-Heteroatom Substituted)Peroxy Compounds

Abstract

The Lewis acid catalyzed ring opening reaction of Donor−Acceptor (D−A) cyclopropanes with alkyl hydroperoxides is reported to furnish various peroxycarbonyls and 1,3-haloperoxygenated compounds in good to excellent yields. This method adds another instance to scarcely reported noncyclilizing 1,3-bisfunctionalization of D−A cyclopropanes with two different functional groups and relies on the dual role of peroxide as nucleophile and oxidant through an orchestrated reaction sequence. The products obtained, including α-heterosubstituted peroxy compounds, are amenable to useful synthetic elaboration.

Lewis acid triggered N-alkylation of sulfoximines through nucleophilic ring-opening of donor–acceptor cyclopropanes: synthesis of γ-sulfoximino malonic diesters

“…After the remarkable achievement of ring-opening of D-A cyclopropane, next, we synthesized γ-sulfoximino, α-bromo malonic diesters 6 by adding an appropriate amount of a halogenating agent (N-bromo succinimide) using the standard reaction conditions, as shown in Scheme 2. 17 Next, the synthetic utility of this reaction was demonstrated through the gram-scale synthesis of 3a (Scheme 3) using 1.96 mmol (1.0 g scale) of 1a with 2.35 mmol of 2a, which pro- a Reaction conditions: 1a (0.17 mmol), 2a-r (0.20 mmol), Sc(OTf) 3 (10 mol%), at 25 °C, 8-16 h, under a N 2 atmosphere. b Isolated yields after column chromatographic purification are shown.…”

“…After the remarkable achievement of ring-opening of D–A cyclopropane, next, we synthesized γ-sulfoximino, α-bromo malonic diesters 6 by adding an appropriate amount of a halogenating agent ( N -bromo succinimide) using the standard reaction conditions, as shown in Scheme 2. 17…”

An Approach to α‐ and β‐Amino Peroxides via Lewis Acid Catalyzed Ring Opening‐Peroxidation of Donor‐Acceptor Aziridines andN‐Activated Aziridines

“…Acid promoted rearrangement of organic peroxides ( i. e ., Hock‐type rearrangement) has been largely explored for important downstream synthetic transformations. In this context, γ‐peroxycarbonyls have lent themselves for the preparation of functionalized furans, pyrroles, carbazole or dibenzo‐xanthene derivatives . Based on the structural similarity of γ‐peroxycarbonyl to α‐ N ‐peroxide, we considered to study compound 3 under Hock‐type rearrangement conditions (Scheme ) in presence of TfOH…”

“…We recently disclosed a catalytic method for alkylperoxide addition to donor‐acceptor (D−A) cyclopropanes . Inherent ring‐strain of D−A cyclopropane largely facilitated the process in presence of a Lewis acid and thus provided a gateway to functionalized peroxides.…”

Lewis acid catalyzed annulation of spirocyclic donor–acceptor cyclopropanes with exo-heterocyclic olefins: access to highly functionalized bis-spirocyclopentane oxindole frameworks

“…8 In this context, development of a method which enables the flexible incorporation of various heterocyclic pharmacophores along with an oxindole nucleus at the two edges of the core cyclopentane ring would be highly desirable for exploring new biologically relevant chemical space (Scheme 1c). 8d,9 In continuation of our investigations to develop new methodologies with DAC, 10 we now demonstrate the utility of oxindoleactivated spiro-DAC for the de novo construction of analogous assembly of spirocyclopentane bis-oxindole systems, for the first time, by successfully developing an efficient [3+2] annulation with challenging exo-heterocyclic alkene partners (Scheme 1c).…”