A facile new procedure for the deprotection of allyl ethers under mild conditions

Hu, Yuping; Dominique, Romyr; Das, Sanjoy K.; Roy, René

doi:10.1139/v00-073

Cited by 56 publications

(20 citation statements)

References 23 publications

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“…The introduction of the phosphocholine residues was performed with cholinoxy‐cyanoethoxy‐diisopropylaminophosphine31 using tetrazole as the activator, and then oxidation using tert ‐butyl hydroperoxide to deliver the desired product in high yield. 1d‐O‐Deallylation was successfully achieved with the [(Ph 3 P) 2 RuCl 2 ] complex32 as the catalyst, thereby leading to double bond migration. Final acid hydrolysis of the resulting enol ether afforded the desired HGFED intermediate 25 .…”

Section: Methodsmentioning

confidence: 99%

Total Synthesis of Lipoteichoic Acid of Streptococcus pneumoniae

et al. 2010

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Section: Methodsmentioning

confidence: 99%

Total Synthesis of Lipoteichoic Acid of Streptococcus pneumoniae

et al. 2010

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“…This assumption gained credence when we noted that the complex 1a was shown by others 4 to be capable of isomerizing allylic ethers to vinyl ethers, although less efficiently than with RuCl 2 (PPh 3 ) 3 , and allylic amines to enamines. 5 Synthetic applications of these processes have now appeared.…”

Section: Figurementioning

confidence: 80%

A Comment on the Gurjar Mechanism for Alkene Isomerization Using the Grubbs Olefin Metathesis Catalysts

Edlin¹,

Faulkner²,

Fengas³

et al. 2005

Synlett

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A C o m m e n t o n t h e G u r j a r M e c h a n i s m f o r A l k e n e I s o m e r i z a t i o nAbstract: The mechanism of allylic alcohol isomerization in the presence of the Grubbs metathesis catalysts is discussed.In a recent study we reported 1 that 1a (Figure 1) serves as an active catalyst in Atom Transfer Cyclization Reactions 2 (ATCR) and noted in one particular example, cyclization of the ester 2a, that the isomerized, unsaturated lactone 5a rather than the chlorolactone 3a was obtained in high yield. This outcome was in variance with that observed when the more traditional Cu(I)-bipy catalyst 3 was employed in this cyclization which indeed resulted in the formation of the chlorolactone 3a, again in high yield. In the case of 1a we reasoned that 5a arose from 3a via isomerization of the alkene 4a (Scheme 1). Figure 1This assumption gained credence when we noted that the complex 1a was shown by others 4 to be capable of isomerizing allylic ethers to vinyl ethers, although less efficiently than with RuCl 2 (PPh 3 ) 3 , and allylic amines to enamines. 5 Synthetic applications of these processes have now appeared. 6 In addition the isomerization of allylic alcohols to aldehydes/ketones using catalytic quantities of 1a has also been noted by several groups. 7 A mechanistic rational (Scheme 2) put forward by Gurjar 8a to account for the latter transformation invokes the formation of a metallacyclobutane 8b,c 6 which can undergo b-hydride elimination 8d to the s-complex 7 which on reductive elimination generates the enol tautomer 8 of the ketonic product 9 with concomitant regeneration the carbene complex 1a. These authors also suggested that minor amounts of a,b-unsaturated ketones 10 apparently arose from decomposition of the s-complex 7. Given that transition metal-catalyzed alkene isomerization reactions in general 13 and allylic alcohol-ketone interconversions in particular 14 have been the focus of a number of mechanistic studies, the novelty of the Gurjar hypothesis made us question the mechanism by which 2a was converted into 5a during our ATCR-isomerization sequence.

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“…Attempts to convert the allyl side chain into the desired ethyl group under oxidative conditions led to extensive decomposition of 11 . However, isomerization of the terminal olefin contained in 11 by the procedure of Roy and co‐workers16 gave the propenyl intermediate 12 successfully in 81 % yield. Cross‐metathesis with ethylene gas, followed by hydrogenation, gave (−)‐tuberostemonine ( 13 ).…”

Section: Methodsmentioning

confidence: 99%

Ruthenium‐Catalyzed Isomerization of Terminal Olefins: Applications to Synthesis

Donohoe¹,

O’Riordan²,

Rosa³

2009

Angew Chem Int Ed

155

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In, out, olefin about: A ruthenium hydride complex derived from the Grubbs second‐generation metathesis catalyst has proven to be an efficient catalyst for the selective isomerization of terminal olefins to the corresponding propenyl derivatives (see scheme). This methodology has been applied in a number of syntheses to enable access to complex natural products. Cy=cyclohexyl, Mes=mesityl, MOM=methoxymethyl.

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A facile new procedure for the deprotection of allyl ethers under mild conditions

Cited by 56 publications

References 23 publications

Total Synthesis of Lipoteichoic Acid of Streptococcus pneumoniae

Total Synthesis of Lipoteichoic Acid of Streptococcus pneumoniae

A Comment on the Gurjar Mechanism for Alkene Isomerization Using the Grubbs Olefin Metathesis Catalysts

Ruthenium‐Catalyzed Isomerization of Terminal Olefins: Applications to Synthesis

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