Rhodium-Catalyzed Alkyne Cyclotrimerization Strategies for C-Aryl Glycoside Synthesis

McDonald, Frank E.; Zhu, Haiyuan; Holmquist, Christopher R.

doi:10.1021/ja00129a030

Cited by 123 publications

(41 citation statements)

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“…The alkynyl glycal precursors of the corresponding dicobalt hexacarbonyl derivatives 1 , were readily prepared from tri‐ O ‐acetyl‐ D ‐glucal ( 3 ) by synthetic sequences consisting of four or five steps, depending on the substituent at O ‐6 (Scheme ). Accordingly, C ‐1‐alkynyl tri‐ O ‐benzyl‐ D ‐glucal derivatives 6 , and 6‐ O ‐silyl derivatives 9 , were prepared by PCC oxidation of intermediates 4 and 7 , leading to lactones 5 and 8 , respectively,20 followed by a sequence of lithium acetylide‐addition/POCl 3 ‐mediated elimination 21…”

Section: Resultsmentioning

confidence: 99%

A Substrate‐Based Approach to Skeletal Diversity from Dicobalt Hexacarbonyl (C1)‐Alkynyl Glycals by Exploiting Its Combined Ferrier–Nicholas Reactivity

Lobo

Gómez

Miranda

et al. 2014

Chemistry A European J

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Novel substrates that combine dicobalt hexacarbonyl propargyl (Nicholas) and pyranose-derived allylic (Ferrier) cations have been generated by treatment of hexacarbonyldicobalt (C-1)-alkynyl glycals with BF3 (.) Et2 O. The study of these cations has resulted in the discovery of novel reaction pathways that have shown to be associated to the nature of O-6 substituent in the starting alkynyl glycals. Accordingly, compounds resulting from ring expansion (oxepanes), ring contraction (tetrahydrofurans), or branched pyranoses, by incorporation of nucleophiles, can be obtained from 6-O-benzyl, 6-hydroxy, or 6-O-silyl derivatives, respectively. The use of a 6-O-allyl alkynyl glycal led to a suitable funtionalized oxepane able to experience an intramolecular Pauson-Khand cyclization leading to a single tricyclic derivative.

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Section: Resultsmentioning

confidence: 99%

A Substrate‐Based Approach to Skeletal Diversity from Dicobalt Hexacarbonyl (C1)‐Alkynyl Glycals by Exploiting Its Combined Ferrier–Nicholas Reactivity

Lobo

Gómez

Miranda

et al. 2014

Chemistry A European J

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“…Consequently, there is significant interest in the development of new synthetic methodologies to access higher para-quinones. Although a number of synthetic methods affording these molecules have been reported [77][78][79][80][81], the most attractive one seems to be the direct cycloaddition of metallacyclopentadienes to quinones. Reaction of zirconacyclopentadienes with quinones 9 in the presence of copper chloride and p-chloranil afforded para-dihydroquinones 10 and quinones 11 (Scheme 9) [82].…”

Section: Cycloaddition Reaction Of Zirconacyclopentadienes To Quinonementioning

confidence: 99%

Zirconacycle-mediated synthesis of carbocycles

Chen

2010

Chin. Sci. Bull.

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Direct transformation of five-membered zirconacycles to carbocyclic compounds is of great synthetic interest. The reaction of zirconacycles with electrophiles containing at least two reactive functional groups or an oxidant affords various carbocycles through cross coupling, addition, and/or oxidative coupling reactions. In this paper, we present our recent results on the zirconacycle-mediated formation of carbocycles, including: (1) 1,1-cycloaddition of oxalyl dichloride with zirconacycles; (2) benzoquinone-promoted coupling of zirconacyclopentadienes in the presence of CuCl; (3) cycloaddition of zirconacyclopentadienes to quinones; (4) cycloaddition of zirconacyclopentadiene with 2-bromoacrylate, 2-bromoacrylaldehyde and 3-bromofuran-2,5-dione in the presence of CuCl; (5) one-pot coupling of two alkynes and an alkene to form cyclohexene derivatives via zirconacyclopentadienes; and (6) dianionic cycloaddition of decatetraenes with esters or acyl chlorides to form nine-membered carbocycles.

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“…The cyclohexadiene 177 was obtained from 176 through an intra- molecular Diels-Alder addition [219], whereas the dihydro-oxepin 179 was prepared in low yields from 178 by means of a [2+2] cycloaddition followed by ring-expansion [220]. Rh-catalyzed cyclotrimerization of the propargyl 1-C-ethynyl-a/b-dglucopyranosides 180 with acetylene gave an 89 % yield of the spiroacetals 181 [221].…”

Section: Cycloadditions and Cyclocondensationsmentioning

confidence: 99%