Synthesis of Carbon-Linked Glycopeptides through Catalytic Asymmetric Hydrogenation

Debenham, Sheryl D.; Debenham, John S.; Burk, Mark J.; Toone, Eric J.

doi:10.1021/ja971324z

Cited by 61 publications

(28 citation statements)

References 11 publications

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“…A last example of a Michael addition to the benzothiazolyl vinyl sulfone 17 gave the complex sulfone 18, a potential Julia-Kociensky reagent (Scheme 33) [158] C-allylation of protected mannosyl bromides with allylic sulfides and sulfones has been reported using a procedure published in the galactose series [159], but no yields were given [34,160] As part of a study of radical-chain desulfurisation of various a-(alkylthiomethyl) acrylates, the allylic sulfide derivative 19 was reacted with triphenylphosphine in the presence of a peroxide initiator (Scheme 34). Radical desulfurisation followed by allylic rearrangement of the reactive intermediate gave the C-mannoside 20 in moderate yield [161].…”

Section: Reaction Conditionsmentioning

confidence: 99%

“…As a C-glycoside, it is present in natural products such as D-mannosyl tryptophan [21][22][23][24][25][26][27][28][29] or chafuroside [30]. It has also been incorporated in synthetic entities such as modified glycosyl amino-acids [31][32][33][34][35], or used in the course of total syntheses, that is a guanofosfocin analogue, for chitine synthase inhibition [36], (À)-daucic acid [37,38], zooxanthellatoxins [39] and the IJK ring framework of brevetoxin B [40]. Various D-Cmannopyranoside derivatives have been synthesized in order to evaluate their biological activity as lectin inhibitors relative to their O-glycoside counterpart [41][42][43][44][45][46][47][48][49][50][51][52][53][54][55][56][57].…”

Section: Introductionmentioning

confidence: 99%

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The synthesis of d-C-mannopyranosides

Choumane¹,

Banchet²,

Probst³

et al. 2010

Comptes Rendus. Chimie

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Section: Reaction Conditionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The synthesis of d-C-mannopyranosides

Choumane¹,

Banchet²,

Probst³

et al. 2010

Comptes Rendus. Chimie

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“…In both series the phosphorus is now part of a five-membered ring that has adjacent stereogenic centers [224,225]. DuPhos has been shown to be useful for the preparation of a-amino acid derivatives [222,[226][227][228][229][230][231][232][233][234][235][236][237][238][239][240][241], including b-branched examples that are not accessible with DIPAMP [222,242,243]. The catalyst system is also successful with enamides, enol acetates, unsaturated carboxylic, and itaconic acids [7,115,222,[244][245][246][247][248][249][250].…”

Section: Duphosmentioning

confidence: 99%

Enantioselective Alkene Hydrogenation: Introduction and Historic Overview

Ager¹

2006

The Handbook of Homogeneous Hydrogenation

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23Enantioselective Alkene Hydrogenation: Introduction and Historic Overview Development of CAMP and DIPAMPDuring the late 1960s, Horner et al. [13] and Knowles and Sabacky [14] independently found that a chiral monodentate tertiary phosphine, in the presence of a rhodium complex, could provide enantioselective induction for a hydrogenation, although the amount of induction was small [15][16][17][18][19][20]. The chiral phosphine ligand replaced the triphenylphosphine in a Wilkinson-type catalyst [10,21,22]. At about this time, it was also found that [Rh(COD) 2 ] + or [Rh(NBD) 2 ] + could be used as catalyst precursors, without the need to perform ligand exchange reactions [23].Knowles found that the monophosphine CAMP (1a) could provide an ee-value of up to 88% for the reduction of dehydroamino acids. CAMP was an extension of PAMP (1b) that provides ee-values of 50-60% in analogous reactions [24]. At this time, Kagan showed that DIOP (2) (vide infra), where the stereogenic centers are not at phosphorus, could also provide enantioselective induction in an hydrogenation. DIOP also showed that a bisphosphine need not have the chirality at phosphorus, and that good stereoselectivity might result from a C 2 -symmetric ligand. Knowles then developed the C 2 -symmetric ligand DIPAMP (3) [22,25]. The use of Rh-DIPAMP for the synthesis of l-Dopa is well known and is still practiced today [12,22,27]. A number of variations of the DIPAMP structure were investigated for the synthesis of this important pharmaceutical, but the parent remains the best ligand in this class [22].

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“…(7), the sense of asymmetric induction was inversed by using the antipode catalysts, where the directivity by chiral catalyst overrides the directivity of substrate [52]. In the case of chiral dehydroamino acids, where both double bond and amide coordinate to the metal, the effect of the stereogenic center of the substrate is negligibly small and diastereoface discrimination is unsuccessful with an achiral rhodium catalyst (see Table 21.1, entries 9 and 10) [9]. …”

Section: Ester Unit-or Amide-directive Hydrogenationmentioning

confidence: 99%

“…In the hydrogenation of double bonds in steroidal compounds, diastereoselectivity induced by iridium catalysts is very high [8]. In the reduction of dehydroamino acid derivatives with a chiral unit, an achiral rhodium catalyst resulted in stereorandom products (Table 21.1, entries 9 and 10) [9]. In the reaction of pyrone, the hydrogenation does not stop at the dihydropyrone stage, and cis-lactone is obtained in high diastereoselectivity, whereas hydrogenation of (R)-dihydropyrone afforded cis-lactone in lower diastereoselectivity, suggesting the complex character of the second hydrogenation step (Table 21.1, entries 13 and 14) [11].…”

Section: Introductionmentioning

confidence: 99%