Ozonolyses of 1-Alkyl-Substituted 3-Methylindenes. Remarkable Effects of the Substituent Steric Bulk and the Stereochemistry of the Carbonyl Oxide Intermediates on the Efficiency of Ozonide Formation

Abstract

Ozonolyses of 3-methyl- and 3-isopropyl-1-methylindenes (1a,b) in ether gave mainly the corresponding oligomers 3a,b, while in the case of 3-phenyl- and 3-tert-butyl-1-methylindenes (1c,d), the corresponding exo−endo mixtures of ozonides 2c,d were obtained in good yield, the exo isomer being the major one. The ozonolyses of two stereoisomeric keto vinyl ethers, (E)-16 and (Z)-16, demonstrated that the stereochemistry of the derived carbonyl oxide 5c exerts a remarkable influence on the course of the reaction. Particularly interesting is the fact that syn-5c having a proper geometry for the concerted cycloaddition provided ozonide 2c in high yield even in the presence of trifluoroacetophenone. The high degree of similarity in the nature and distribution of the products from the ozonolyses of keto olefin (E)-16 and 1-methyl-3-phenylindene (1c) would be consistent with their respective reactions proceeding predominantly through a common carbonyl oxide intermediate syn-5c.

Synthesis of 4‐Aryl‐8‐fluoro‐3a,4,5,9b‐tetrahydro‐3H‐cyclopenta[c]quinolines and Their Ozonides

“…As noted earlier, according to the X-ray analysis, the formation of ozonides of substituted tetrahydrocyclopenta[c]quinolines occurs regio-and stereoselectively [12]. Instead of broadened signals of C(1) and C(2) in 13 C-NMR spectra of the starting compounds (d(C) 128.8 -130.6 ppm), spectra of the compounds 11 -13b contained narrow signals in the typical field for ozonides (d(C) 98.7 -99.2 ppm) [12] [13], confirming the transformation of the C¼C bond into a 1,2,4-trioxolane ring. The cross- peak in the HMBC spectrum of ozonide 11 between the signal at d(C) 98.7 ppm and that at d(H) 3.56 (HÀC(11b)) was unambiguously assigned to C(1), as well as a signal at (d(C) 99.1 ppm was attributed to C(4).…”

“…ESI-MS: 443 ([M] þ ). rel-2,2,2-Trifluoro-1-[(1R,4S,5aR,6S,11bS)-10-fluoro-6-(2-fluorophenyl)-1,4,5,5a,6,11b-hexahydro-7H-1,4-epoxy [1,2]dioxepino [5,4-c]quinolin-7-yl]ethanone (12). Yield: 68%.…”

“…The [M À H] À ion peaks in ESI mass spectra of 11 -13 provided their molecular weights. According to 1 H-and 13 C-NMR spectra, and the X-ray diffraction data reported earlier for related ozonides [10] [12], the newly obtained ozonides 11 -13 were identified as (1R*,4S*, 5aR*,6S*,11bS*)-6-aryl-10-fluoro-4,5,5a,6,7,11b-hexahydro-7-(trifluoroacetyl)-1H-1,4epoxy- [1,2]dioxepino [5,4-c]quinolines (Table 3).…”

Recent Advances in the Chemistry of Cyclic Peroxides

“…alkoxy hydroperoxide are often formed in appreciable quantities (Scheme 76) [161] (Scheme 78) [75]. The related hydroperoxide 237 is converted into the peroxy lactone 238 on treatment with a mixture of acetic anhydride and triethylamine [75].…”

Transformations of peroxide products of olefins ozonolysis

“…One more effi cient reducer of the peroxide ozonolysis products to carbonyl compounds is triphenylphosphine that reduces the ozonolysis product unlike Me 2 S fast and without the formation of abnormal reaction products [64][65][66][67][68][69][70].…”