Ionic reactions of carbon tetrachloride. Survey of reactions with ketones, alcohols, and sulfones

Meyers, Cal Y.; Malte, A. M.; Matthews, Walter S.

doi:10.1021/ja01054a049

Cited by 171 publications

(73 citation statements)

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“…[1][2][3][4][5][6] Although some control in the geometry of the double bond formed can be achieved, in acyclic examples mixtures of cis-and trans-alkenes are often formed. [1][2][3][4][5][6] Typically α-chloro and bromo sulfones, preformed [1][2][3][4][5][6] or generated in situ, [1][2][3][4][5][6][7][8][9] are employed and mechanistically this halide leaving group is essential, enabling the rate-determining episulfone ring-closure process to occur.…”

Section: Introductionmentioning

confidence: 99%

The Epoxy‐Ramberg–Bäcklund Reaction (ERBR): A Sulfone‐Based Method for the Synthesis of Allylic Alcohols

2006

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Section: Introductionmentioning

confidence: 99%

The Epoxy‐Ramberg–Bäcklund Reaction (ERBR): A Sulfone‐Based Method for the Synthesis of Allylic Alcohols

2006

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“…Indeed, if a nucleophile such as pmethoxy-a-toluenethiol was added at À30 8C after 11 had been exposed to TsOH for 5 h and the reaction medium was then concentrated to near dryness, sulfide 16 was obtained in 57 % overall yield. [15] This new tetraaryl intermediate could then be converted into the natural product ampelopsin D (2) through a highly selective Ramberg-Bäcklund reaction [16] under Meyers modified conditions [17] that afforded permethylated ampelopsin D along with its chromatographically separable Z-olefin isomer in a 5:1 ratio (40 % and 7 % yield over two steps, respectively), followed by Lewis acid mediated phenol deprotection using BBr 3 . [18] Subsequent treatment of 2 with five equivalents of HCl in MeOH at 80 8C effected olefin isomerization to give isoampelopsin D (17) in near quantitative yield.…”

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Total Synthesis of Resveratrol‐Based Natural Products: A Chemoselective Solution

2007

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“…The RambergÀB‰cklund reaction of the bisallylic sulfone 9 under Meyer×s conditions [15] at ambient temperature produced compound 10 containing the central conjugated triene moiety in 63% yield. The presence of a small amount (less than 10%) of a stereoisomer of compound 10, presumably the (15Z)-isomer, was also observed in 1 H-NMR spectrum.…”

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Allylic Sulfones Containing Triene Moieties as Key Synthons for Carotenoid Synthesis

Choi

Jeong

et al. 2003

Helvetica Chimica Acta

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An efficient synthetic method for the allylic sulfone 2 containing a conjugated triene moiety has been proposed involving i) coupling of allylic sulfones 4 with the C 5 bromoallylic sulfide 5, ii) base-promoted dehydrosulfonation in the presence of allylic sulfide, and iii) selective oxidation of the resulting trienyl sulfide to the corresponding sulfone. Total synthesis of lycopene starting from the C 15 allylic sulfone 2b has been described, where the new C 10 bis(chloroallylic) sulfone 11 proved to be a useful substitute for the C 10 bis(chloroallylic) sulfide 3, which did not require the problematic chemoselective sulfur oxidation in a conjugated polyene.Introduction. ± Carotenoids such as b-carotene (1a) and lycopene (1b) are characterized by long conjugated polyene chains that show distinctive red colors and are ideally utilized as nonhazardous dyes for foodstuffs. High reactivity of these polyenes with activated carcinogenic oxygen or radicals provides carotenoids with prophylactic effects against certain cancers of the pancreas, the mouth, and the bladder, etc.[1]. Among the numerous approaches that have appeared in the literature to build the conjugated polyene chains of carotenoids [2], methods based on acetylide coupling/ partial hydrogenation [3] and Wittig olefination [4] have been the two main synthetic approaches. The Julia sulfone olefination protocol [5], which has been applied to retinol synthesis [6], is presumed to be the best method to produce double bonds with the (E)-configuration [7]. We have introduced the C 10 bis(chloroallylic) sulfide 3 as a stable substitute for the highly unstable 1,8-dichloro-2,7-dimethylocta-2,4,6-triene, and successfully accomplished total syntheses of b-carotene (1a) and lycopene (1b) based on the Julia sulfone-olefination protocol [8]. To generalize this process with C 10 bis(chloroallylic) sulfide 3 for carotenoid syntheses, an efficient method should be devised to build allylic sulfones containing conjugated CC bonds such as 2 (Scheme 1). We herein report our strategy to synthesize allylic sulfones comprising a conjugated triene moiety and total synthesis of lycopene [9] by means of the allylic sulfone 2b.

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Ionic reactions of carbon tetrachloride. Survey of reactions with ketones, alcohols, and sulfones

Cited by 171 publications

References 1 publication

The Epoxy‐Ramberg–Bäcklund Reaction (ERBR): A Sulfone‐Based Method for the Synthesis of Allylic Alcohols

The Epoxy‐Ramberg–Bäcklund Reaction (ERBR): A Sulfone‐Based Method for the Synthesis of Allylic Alcohols

Total Synthesis of Resveratrol‐Based Natural Products: A Chemoselective Solution

Allylic Sulfones Containing Triene Moieties as Key Synthons for Carotenoid Synthesis

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