3‐Spirocyclopropanedihydro‐ and ‐tetrahydropyridin‐4‐ones from Nitrone Cycloadducts of Bicyclopropylidene via 1‐(1′‐Aminomethylcyclopropyl)cyclopropanol under Pd^II Catalysis

Abstract

A series of 3‐spirocyclopropanedihydro‐ and ‐tetrahydropyrid‐4‐ones have been synthesized by nitrone cycloaddition to 1,1′‐bicyclopropylidene (BCP), chemoselective reduction of the N–O bond of the isoxazolidine ring, and PdII‐catalyzed cascade rearrangement of the β‐aminocyclopropanol derivatives into the final products. The new tetrahydropyridone derivatives were also prepared by thermal rearrangement of the isoxazolidines. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

Selective Carbon–Carbon Bond Cleavage of Cyclopropanols

“…This strategy has also been used in the context of making spirocyclopropyl dihydropyrin-4-ones such as 9c. 20 A related domino-type process is the Heck-type arylation of ring-opened enone derivatives, recently reported by Hurski (Scheme 4). 21 In this report, the authors first describe conditions for the ring opening and β-hydride elimination of cyclopropyl alcohols tethered to oxazoline directing groups (10), where the products are linear (11) and branched (12) enone regioisomers (Scheme 4a).…”

Rh-Catalyzed rearrangement of vinylcyclopropane to 1,3-diene units attached to N-heterocycles

“…Wittig olefination of ketones 8 , anti - 12 and 16 [ 43 ] with MePPh 3 Br/ t -BuOK in THF at room temperature gave the VCPs 14 , 15 , and 17 in good yields (53–96%) ( Scheme 4 , see Supporting Information File 1 for full experimental data). The configuration was retained under the reaction conditions in compounds 15 and 17 , as ascertained by the unique set of 1 H NMR signals in the crude reaction mixture.…”

3-Benzyl-3-hydroxy-2-phenyl-3H-indole 1-oxide

“…For the use of nitrones in the spin-trapping technique and in organic synthesis, see: Janzen (1971); Zubarev (1979); Balasubramanian (1985); Pisaneschi et al (2002); Jones et al (2000); Bernotas et al (1999); Ali & Wazeer (1988); Merino (2005); Chiacchio et al (2006); Revuelta et al (2008); Astolfi et al (2003); Greci et al (2001); Tommasi et al (1999); Bruni et al (1998). For a related structure, see: Yamada et al (2003).…”

“…Moreover, a series of 3-spirocyclopropane dihydro-and tetrahydropyrid-4-ones were synthesized by nitrone cycloaddition to 1,1'-bicyclopropylidene (Revuelta et al, 2008). The title compound was synthesized in order to continue our studies on 1,3-dipolar cycloaddition with different dipolarophiles, with particular focus on the catalytic activity of metal cations such as cobalt(II), calcium(II), zinc(II) and nickel(II) (Astolfi et al, 2003;Greci et al, 2001;Tommasi et al, 1999;Bruni et al, 1998).…”