Abstract:1-Bromobicyclo[1.1.1]pentane (3) is found to undergo solvolysis faster than t-butyl bromide in 80% aqueous ethanol, and gives 3-methylenecyclobutanol (7) exclusively. Products arising from capture of the bicyclo[1.1.1] pentyl cation (5) were not detected.
“…The bridgehead radicals generated thermally, photochemically, or electrochemically from the carboxylic acids, tert -butyl peroxyesters 49 , or Barton esters 202 , react with a number of hydrogen, ,, carbon, , halogen, ,,,,,,,,,− phosphorus, sulfur, , and other 236,278 radical traps (Scheme and Table ). 76 …”
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“…The bridgehead radicals generated thermally, photochemically, or electrochemically from the carboxylic acids, tert -butyl peroxyesters 49 , or Barton esters 202 , react with a number of hydrogen, ,, carbon, , halogen, ,,,,,,,,,− phosphorus, sulfur, , and other 236,278 radical traps (Scheme and Table ). 76 …”
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
“…The tube was allowed to warm to room temperature and left to stand overnight to ensure complete reaction before being analyzed by 1 H and 13 C NMR. The known spectral properties of the acids 1 (Y = COOH; X = F, Cl, Br, CF 3 , and COOCH 3 43 ), the fluorides 1 (Y = F; X = Cl, CF 3 , and COOCH 3 ) 5 , and several 1-substituted (X) bicyclo[1.1.1]pentanes 1 (Y = H; X = Cl, CF 3 , and COOCH 3 ) facilitated the assignments. The 13 C chemical shifts of the methylene carbons (C2) of the various products were unambiguously assigned by additivity methodology utilizing appropriate 13 C SCS data (Cl, 6.09 ppm; CF 3 , −2.26 ppm; COOCH 3 , 0.56 ppm).…”
A series of 3-halo-substituted bicyclo[1.1.1]pentane-1-carboxylic acids 1 (Y = COOH; X = F, Cl, Br, I, and CF(3)) as well as the parent compound 1 (Y = COOH, X = H) have been prepared, and a study of some of their properties have been made. It was found that their reactions with xenon difluoride cover a wide range of reactivities. On one hand, the fluoro acid 1 (Y = COOH, X = F) displayed no apparent reaction at all while, on the other, the bromo acid 1 (Y = COOH, X = Br) and parent compound 1 (Y = COOH, X = H) underwent ready reaction with complete disintegration of the ring system. A possible explanation is advanced based on polar kinetic and thermodynamic effects governing the lifetime of an intermediate acyloxy radical species. The relative ease of oxidation of the carboxylates 1 (Y = COO(-); X = H, F, Cl, Br, I, CF(3), and COOCH(3)), as mirrored by their peak oxidation potential values (E(p)) determined by cyclic voltammetry, also covers a wide range. These data coupled with the dissociation constants (pK(a)) of some of the acids 1 (Y = COOH; X = H, F, Cl, and CF(3)) reflect significantly on the modes of transmission of electronic effects acting through the bicyclo[1.1.1]pentane ring system.
“…Among the three strategies, the lithium‐metalloid exchange process (Scheme B) should be the most efficient method to afford 9 , followed by the process of LiDBB reduction of 8 (Scheme A) and, finally, the lithium‐halogen exchange process (Scheme C) for the reasons listed below. First, most of the reported syntheses of 1‐halobicyclo[1.1.1]pentanes ( 12‐ ‐ 14 ) require Barton halo‐decarboxylation as the key step . This process usually requires multi‐step synthesis; moreover, the key intermediate, bicyclo[1.1.1]pentane‐1‐carboxylic acid ( 18 ), is most efficiently prepared using BCP−Li ( 9 , see Section 2.2) .…”
Section: Syntheses Of 1‐substituted Bcpsmentioning
confidence: 99%
“…First, most of the reported syntheses of 1‐halobicyclo[1.1.1]pentanes ( 12‐ ‐ 14 ) require Barton halo‐decarboxylation as the key step . This process usually requires multi‐step synthesis; moreover, the key intermediate, bicyclo[1.1.1]pentane‐1‐carboxylic acid ( 18 ), is most efficiently prepared using BCP−Li ( 9 , see Section 2.2) . The only exception is that 1‐chlorobicyclo[1.1.1]pentane ( 12 ), the inactive analogue, could be achieved in 1 step from 2 by hydrogen atom transfer chemistry .…”
Section: Syntheses Of 1‐substituted Bcpsmentioning
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