An Efficient Method for the Synthesis of 2′,3′-Nonsubstituted Cycloalkane-1,3-dione-2-spirocyclopropanes Using (2-Bromoethyl)diphenylsulfonium Trifluoromethanesulfonate

Abstract

An efficient and practical synthesis of 2′,3′-nonsubstituted cyclohexane-1,3-dione-2-spirocyclopropanes using a sulfonium salt was achieved. The reaction of 1,3-cyclohexanediones and (2-bromoethyl)diphenylsulfonium trifluoromethanesulfonate with powdered K 2 CO 3 in EtOAc at room temperature (r.t.) provided the corresponding spirocyclopropanes in high yields. The synthetic method was also applied to 1,3-cyclopentanedione, 1,3-cycloheptanedione, 1,3-indanedione, acyclic 1,3-diones, ethyl acetoacetate, and Meldrum's acid.

Direct Oxidation of Cyclopropanated Cyclooctanes as a Synthetic Approach to Polycyclic Cyclopropyl Ketones

“…It should be noted that although this reaction is widely used for open‐chain compounds, it is not trivial for cyclic diketones. To the best of our knowledge, the only dicarbonyl compound that has been reported to undergo this process is 1 H ‐indene‐1,3(2 H )‐dione; alicyclic compounds such as cyclohexane‐1,3‐dione and dimedone could not be dialkylated through treatment with dibromoethane, but formed O ‐alkylation products exclusively.…”

An Efficient Route to Highly Substituted Indoles via Tetrahydroindol‐4(5H)‐one Intermediates Produced by Ring‐Opening Cyclization of Spirocyclopropanes with Amines

“…The C7-selective methylation of 6-methyltetrahydroindol-4(5H)-ones 2b (R = Ph) and 2c (R = H) [23] with LiHMDS andm ethyl iodide, followed by C5-selective methylation with LDA and methyl iodide, afforded 5,6,7-trimethyl derivatives 24 a and 24 b in 88 and7 4% yield, respectively.A fter oxidation of 24 a and 24 b with chloranil, C4selectivem ethylation of pyrroles 25 a and 25 b with methyllithium,f ollowedb yo xidation of conjugated olefins 26 a and 26 b with chloranil, gave 4,5,6,7-tetramethylindoles 27 a and 27 b in 59 and 79 %yield, respectively. The C7-selective methylation of 6-methyltetrahydroindol-4(5H)-ones 2b (R = Ph) and 2c (R = H) [23] with LiHMDS andm ethyl iodide, followed by C5-selective methylation with LDA and methyl iodide, afforded 5,6,7-trimethyl derivatives 24 a and 24 b in 88 and7 4% yield, respectively.A fter oxidation of 24 a and 24 b with chloranil, C4selectivem ethylation of pyrroles 25 a and 25 b with methyllithium,f ollowedb yo xidation of conjugated olefins 26 a and 26 b with chloranil, gave 4,5,6,7-tetramethylindoles 27 a and 27 b in 59 and 79 %yield, respectively.…”

“…Having achieved the regioselective alkylation of tetrahydroindol-4(5H)-one 2,w ethen investigated the synthesis of indoles possessing fully substituted benzene rings, such as 4,5,6,7-tetramethylindoles 27 a and 27 b (Scheme 9). The C7-selective methylation of 6-methyltetrahydroindol-4(5H)-ones 2b (R = Ph) and 2c (R = H) [23] with LiHMDS andm ethyl iodide, followed by C5-selective methylation with LDA and methyl iodide, afforded 5,6,7-trimethyl derivatives 24 a and 24 b in 88 and7 4% yield, respectively.A fter oxidation of 24 a and 24 b with chloranil, C4selectivem ethylation of pyrroles 25 a and 25 b with methyllithium,f ollowedb yo xidation of conjugated olefins 26 a and 26 b with chloranil, gave 4,5,6,7-tetramethylindoles 27 a and 27 b in 59 and 79 %yield, respectively.…”

The Topological Variable Computation for a Special Type of Cycloalkanes

“…More contexts on cycloalkanes and its applications can refer to El-Sayed et al [30], Vásquez-Espinal et al [31], Caroen et al [32], Denicourt-Nowicki et al [33], El-Gamal et al [34,35], Lepori et al [36], Nambu et al [37], Lazić et al [38], Alaoui et al [39], and Pi-Boleda et al [40]. Since cycloalkanes commonly appeared in the chemical compound and possess wide engineering applications in the field of biology, medicine, and pharmacy, it inspires us to study the characterization of cycloalkanes from mathematical point of view.…”