Facile Palladium-Mediated Conversion of Ethanethiol Esters to Aldehydes and Ketones

Tokuyama, Hidetoshi; Yokoshima, Satoshi; Yamashita, Tohru; Shao-Cheng, Lin; Li, Leping; Fukuyama, Tohru

doi:10.1590/s0103-50531998000400011

Cited by 61 publications

(24 citation statements)

References 4 publications

(4 reference statements)

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“…This inaccessibility was observed once more upon attempts to reduce thioester 4 to aldehyde 6 with either DIBAL-H or a Fukuyama reduction (Pd/C, Et 3 SiH). 24 …”

Section: ■ Results and Discussionmentioning

confidence: 99%

Stereoselective Synthesis of 1-Tuberculosinyl Adenosine; a Virulence Factor of Mycobacterium tuberculosis

et al. 2016

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Despite its status as one of the world’s most prevalent and deadly bacterial pathogens, Mycobacterium tuberculosis (Mtb) infection is not routinely diagnosed by rapid and highly reliable tests. A program to discover Mtb-specific biomarkers recently identified two natural compounds, 1-tuberculosinyl adenosine (1-TbAd) and N6-tuberculosinyl adenosine (N6-TbAd). Based on their association with virulence, the lack of similar compounds in nature, the presence of multiple stereocenters, and the need for abundant products to develop diagnostic tests, synthesis of these compounds was considered to be of high value but challenging. Here, a multigram-scale stereoselective synthesis of 1-TbAd and N6-TbAd is described. As a key-step, a chiral auxiliary-mediated Diels–Alder cycloaddition was developed, introducing the three stereocenters with a high exo endo ratio (10:1) and excellent enantioselectivity (>98% ee). This constitutes the first entry into the stereoselective synthesis of diterpenes with the halimane skeleton. Computational studies explain the observed stereochemical outcome.

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“…This inaccessibility was observed once more upon attempts to reduce thioester 4 to aldehyde 6 with either DIBAL-H or a Fukuyama reduction (Pd/C, Et 3 SiH). 24 …”

Section: ■ Results and Discussionmentioning

confidence: 99%

Stereoselective Synthesis of 1-Tuberculosinyl Adenosine; a Virulence Factor of Mycobacterium tuberculosis

et al. 2016

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“…The reduction of 31 with triethylsilane and Pd/C gave aldehyde 32 in 82% yield 47. Asymmetric allylation of aldehyde 32 was accomplished in 50% yield with B -allyl-(10 S )-(trimethylsilyl)-9-borabicyclo[3.3.2]decane (prepared in situ from 9-[(1 R ,2 R )-pseudoephedrinyl]-(10 S )-(trimethylsilyl)-9-borabicyclo[3.3.2]decane and allylmagnesium bromide 48.…”

Section: Chemistrymentioning

confidence: 99%

Synthetic studies of neoclerodane diterpenes from Salvia divinorum: role of the furan in affinity for opioid receptors

Simpson¹,

Lovell²,

Lozama³

et al. 2009

Org. Biomol. Chem.

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Further synthetic modification of the furan ring of salvinorin A (1), the major active component of Salvia divinorum, has resulted in novel neoclerodane diterpenes with opioid receptor affinity and activity. A computational study has predicted 1 to be a reproductive toxicant in mammals and is suggestive that use of 1 may be associated with adverse effects. We report in this study that piperidine 21 and thiomorpholine 23 have been identified as selective partial agonists at kappa opioid receptors. This indicates that additional structural modifications of 1 may provide ligands with good selectivity for opioid receptors but with reduced potential for toxicity.

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“…To test this analysis, cross-coupling experiments (with N-Cbz-Phe-SPh, PhB(OH) 2 and CuTC) were carried out using 2.5 mol % Pd 2 (dba) 3 as a precatalyst in combination with different phosphorus ligands. Among tris-2-furylphosphine, SbPh 3 , P(OMe) 3 , P(OEt) 3 , P(OBu) 3 , and P(OPh) 3 as supporting ligands (20 mol % each), P(OEt) 3 delivered the best proved performance.…”

Section: A Room Temperature Synthesis Of High Enantiopurity N-cbz α-Amentioning

confidence: 99%

Ambient Temperature Synthesis of High Enantiopurity N-Protected Peptidyl Ketones by Peptidyl Thiol Ester−Boronic Acid Cross-Coupling

et al. 2007

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Abstractα-Amino acid thiol esters derived from N-protected mono-, di-, and tripeptides couple with aryl, π-electron-rich heteroaryl, or alkenyl boronic acids in the presence of stoichiometric Cu(I) thiophene-2-carboxylate (CuTC) and catalytic Pd 2 (dba) 3 /triethylphosphite to generate the corresponding Nprotected peptidyl ketones in good to excellent yields and in high enantiopurity. Triethylphosphite plays a key role as a supporting ligand by mitigating an undesired palladium-catalyzed decarbonylation-β-elimination of the α-amino thiol esters. The peptidyl ketone synthesis proceeds at room temperature under non-basic conditions and demonstrates a high tolerance to functionality.

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Facile Palladium-Mediated Conversion of Ethanethiol Esters to Aldehydes and Ketones

Cited by 61 publications

References 4 publications

Stereoselective Synthesis of 1-Tuberculosinyl Adenosine; a Virulence Factor of Mycobacterium tuberculosis

Stereoselective Synthesis of 1-Tuberculosinyl Adenosine; a Virulence Factor of Mycobacterium tuberculosis

Synthetic studies of neoclerodane diterpenes from Salvia divinorum: role of the furan in affinity for opioid receptors

Ambient Temperature Synthesis of High Enantiopurity N-Protected Peptidyl Ketones by Peptidyl Thiol Ester−Boronic Acid Cross-Coupling

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