The michael induced ramberg-bäcklund homologation to conjugated isoprenoids

Burger, Julian; Chen, T.B.R.A.; Waard, E.R. de; Huisman, H. O.

doi:10.1016/s0040-4020(01)92030-7

Cited by 22 publications

(9 citation statements)

References 8 publications

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“…(12.5 g, 0.129 mol) at r.t. for 6 h to give (2Z)-2b (3.91 g, 11.4 mmol) and (all-E)-2b (9.79 g, 28.4 mmol) in 22 and 55% yields, resp. 3,7-Dimethyl-1-(phenylsulfonyl)octa-2,4,6-triene (2c) [16]. According to the general procedure for 2a, a soln.…”

Section: Experimental Partmentioning

confidence: 99%

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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Section: Experimental Partmentioning

confidence: 99%

Allylic Sulfones Containing Triene Moieties as Key Synthons for Carotenoid Synthesis

Choi

Jeong

et al. 2003

Helvetica Chimica Acta

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“…Natural heterocycles are constructed by intramolecular binding of the sulfenium cation to various nucleophilic traps. The C=C bonds other than those present in indoles can serve as nucleophiles as exemplified by the ingenious synthesis of the alkaloid (AE)-3-demethoxyerythratidinone (153). 97 The latter was prepared starting from substituted sulfinylacetamide 154, which was subjected to double cyclisation via intermediate A.…”

Section: Synthesis Of Cyclic Compounds By Intramolecular Reactions Of...mentioning

confidence: 99%

“…Burger et al 153 failed to elaborate the stereoselective synthesis by decreasing the basicity of the reaction medium through the generation of the required anion by the addition of the sulfinate anion to a-halogenovinyl-(266) or butadienyl sulfones 267 [the so-called MIRB process (Michael Induced Ramberg ± BaÈ klund)]. Starting from sulfones 268 and 269, this procedure also yielded mixtures of stereoisomeric isoprenoinds.…”

Section: Ch2c(mementioning

confidence: 99%

See 1 more Smart Citation

Rearrangements of sulfoxides and sulfones in the total synthesis of natural compounds

Prilezhaeva¹

2001

Russ. Chem. Rev.

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AbsbaCL An alomcdly ordered PdCu&o.p hydride was spthesizcd at 600 K and a hydxogcn p m s m of 3 GPa Irs Netd lanice had B primitive temgonal cell fomcd from the initial K c cell of thc disordcred PdCu alloy due to ordcrbg of the Pd and Cu atoms into allemve la)cn perpendicul;lr to the tetragonal c-ais. Rietveld refinemcat of Ihe neumn diffraction pallem of P d C u b 9 m a u r e d ai 80 K showcd thc H ~o m s to occupy octahedral interstitials within thc Pd layers. The inclastic neumu scanering sNdy at 35 K revealed a broad hydrogen o p i d peak with pcculivlties at energy m s f c n of 79 and 95 meV and of I13 meV uhich wcre zcribed to the H vibrations in the P d H planes and dong thc CU-H chains perpendiculv to the planer, respectively. The paantid for hydmgen *OM in the PdCK+9 ordered phase was thus noticeably diffcrenc even in the Pd-H plane, from that in the h o u n hydrides of pdhdium and palladium alloys. The value of approximly 116 meV was predicted forthc l o d H vibntions in dilute Cu-H solid solutions. E G 1991 Physica B 174 25741 Sov. Phys.-Solid State 33 87-90 Calcu&fions: User Manual (IFF KFA, Jiilich) Jiil-Spa-366 Rev. B 36 8798-801 A I, Bashkin IO, Sinicyn V V and Ponyatovskii E G 1989 Physlca C 162-164 1369-70 Belushkin A V 1993 Phys. Solid Srate 35 99-103

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“…The strengths of the procedure from a synthetic perspective are: (i) the ease with which the requisite sulfones can be constructed and the conjunctive nature of the sequences, (ii) the unambiguous location of the resulting alkene moiety and the applicability of the procedure to all alkene substitution patterns including tetrasubstituted variants, (iii) the efficiency with which strained alkenes (e.g. cyclobutenes, unsaturated cyclophanes) 2,3 can be prepared, (iv) the applicability of the procedure to conjugated polyene synthesis, either by using allylic sulfones 2 or via the vinylogous 4 and Michael-induced 5 variants of the Ramberg-Bäcklund rearrangement. Predictably high stereocontrol is not a feature of the Ramberg-Bäcklund rearrangement, but in general Z-alkenes predominate when mild bases are employed, whereas stronger bases favour Ealkenes.…”

Section: (A) Introductionmentioning

confidence: 99%

Recent developments in Ramberg–Bäcklund and episulfone chemistry

Taylor¹

1999

Chem. Commun.

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The michael induced ramberg-bäcklund homologation to conjugated isoprenoids

Cited by 22 publications

References 8 publications

Allylic Sulfones Containing Triene Moieties as Key Synthons for Carotenoid Synthesis

Allylic Sulfones Containing Triene Moieties as Key Synthons for Carotenoid Synthesis

Rearrangements of sulfoxides and sulfones in the total synthesis of natural compounds

Recent developments in Ramberg–Bäcklund and episulfone chemistry

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