Oxidation of Alcohols with o-Iodoxybenzoic Acid in DMSO: A New Insight into an Old Hypervalent Iodine Reagent

Frigerio, M.; Santagostino, Marco; Sputore, Simona; Palmisano, Giovanni

doi:10.1021/jo00127a036

Cited by 362 publications

(172 citation statements)

References 0 publications

Supporting

Mentioning

159

Contrasting

Unclassified

Order By: Relevance

“…4). Compound 8 was obtained from known allyl alcohol 5 20) through Johnson-Claisen rearrangement, reduction of the resultant ester to alcohol, oxidation with IBX, 21) reductive amination, and chlorocarbonylation with triphosgene. Chloroformamide 8 was found to be stable for aqueous extraction, silica gel column chromatography and storage in refrigerator for several weeks, as expected.…”

mentioning

confidence: 99%

Toward General Access to the <i>Aspidosperma</i>-Type Terpenoid Indole Alkaloids: Synthesis of the Key 3,3-Disubstituted Piperidones through Enantioselective Intramolecular Heck-Type Reaction of Chloroformamides

2008

View full text Add to dashboard Cite

An enantioselective intramolecular Heck-type reaction of chloroformamides has been developed for the synthesis of 3,3-disubstituted piperidones. The desired piperidone was formed in the presence of a palladium catalyst, an optically active phosphoramidite ligand, K 3 PO 4 and Ag 3 PO 4 . The obtained piperidone was converted to epieburnamonine.Key words enantioselective reaction; total synthesis; terpenoid indole alkaloid Chem. Pharm. Bull. 56(11) 1567-1574 (2008) © 2008 Pharmaceutical Society of Japan * To whom correspondence should be addressed. e-mail: takemoto@pharm.kyoto-u.ac.jp under normal conditions (entries 1-3). However, lactam 9 was isolated in 60% yield when Ag 3 PO 4 was added to the reaction (entry 4). The combination of Pd 2 (dba) 3 and BINAP was also able to promote the cyclization in the presence of Ag 3 PO 4 (entry 5). Nolan's NHC catalyst was not effective (entry 6).With these results in hand, syntheses of each cis-trans isomer of alkenyl chloroformamide 2 were performed. Alkene (E)-4 was synthesized through hydroalumination as a key step (Fig. 5). 4-Pentyn-1-ol (10) was transformed into alcohol 11 through oxidation, acetalization, and hydroxymethylation using benzotriazolylmethanol (BtCH 2 OH). 22) Alcohol 11 was then subjected to the hydroalumination-iodination sequence 23,24) to give (Z)-iodo alkene 12, whose configuration was confirmed by NOE experiment. Ethylation by Suzuki coupling, followed by benzylation gave the desired alkene (E)-4.Change of the starting material afforded the alternative stereoisomer (Fig. 6). (Z)-Iodoalkene 14 was synthesized from 2-pentyn-1-ol (13) through hydroalumination and iodination. Since benzylation of the hydroxy group under either basic or acidic conditions competed with decomposition of the starting material, protection by THP group was carried out. The resultant THP ether 15 underwent Negishi coupling with 3,3-(dimethoxy)propylzinc chloride 16. 25) Selective hydrolysis of the THP ether and benzylation afforded the desired alkene (Z)-4.Alkenyl acetals (E)-4 and (Z)-4 were coupled with tryptamine 3 26) through hydrolysis and reductive amination to give amines (E)-17 and (Z)-17, respectively (Fig. 7). These compounds were converted to the corresponding chloroformamides (E)-2 and (Z)-2 by treating with triphosgene and Et 3 N.Before the enantioselective Heck-type reaction, a racemic reaction was attempted to find out a suitable palladium source ( Table 2). The cyclized product 1 was isolated after hydrolysis of the resultant enol ether. At the early stage, poor reproducibility was a serious problem. After several attempts, it was found that the activity of the catalyst is highly associated with the conditions used to mix palladium sources and ligands prior to the addition of chloroformamide 2. When [Pd(h 3 -C 3 H 5 )Cl] 2 was premixed with (p-tol) 3 P at 30°C for 30 min, the disappearance of 2 was slow and the yield was 30% after 24 h (entry 1). In contrast, the starting material disappeared in 3 h and yield reached 49% when premixing was performed at 40°C...

show abstract

mentioning

confidence: 99%

Toward General Access to the <i>Aspidosperma</i>-Type Terpenoid Indole Alkaloids: Synthesis of the Key 3,3-Disubstituted Piperidones through Enantioselective Intramolecular Heck-Type Reaction of Chloroformamides

2008

View full text Add to dashboard Cite

show abstract

“…This method combines the advantages of polymer-supported reagents with the advantages of IBX which is superior to the Dess-Martin reagent in stability, efficiency and versatility. 7 The reduced form of reagent 7 is easily separated by simple filtration and can be regenerated by oxidation with oxone. 19 The products are obtained in high purity.…”

Section: Discussionmentioning

confidence: 99%

“…[1][2][3][4][5][6] They can be used for a wide range of chemical transformations, especially as reagents for oxidations. [7][8][9][10][11] For these purposes, iodinanes like (diacetoxyiodo)-benzene,…”

Section: Introductionmentioning

confidence: 99%

First synthesis and oxidative properties of polymer-supported IBX

Mülbaier¹,

Giannis²

2003

Arkivoc

View full text Add to dashboard Cite

A polymer-supported analogue of the IBX-reagent (1-hydroxy-1,2-benziodoxol-3(1H)-one 1-oxide) has been synthesized. Synthesis and oxidative properties of this new and efficient reagent are described. With this reagent is it now possible to oxidize alcohols selectively to the corresponding ketones and aldehydes. Over oxidation to carboxylic acids has not been observed. This new reagent combines the advantages of polymer-supported reagents with those of the IBX reagent.

show abstract

“…Preparation of Pyroglutaminal (5-Oxo-pyrrolidine-2-carbaldehyde)-Pyroglutaminal was synthesized by the one step method of Frigerio et al (14). To a stirred solution of 5-hydroxymethyl-2-pyrrolidinone (1.03 g, 8.96 mmol) in Me 2 SO (10 ml) at room temperature was added oiodoxybenzoic acid (3.03 g, 10.9 mmol).…”

Section: Methodsmentioning

confidence: 99%

The Mechanism of Substrate Recognition of Pyroglutamyl-peptidase I from Bacillus amyloliquefaciens as Determined by X-ray Crystallography and Site-directed Mutagenesis

Itō

Inoue

Takahashi

et al. 2001

Journal of Biological Chemistry

View full text Add to dashboard Cite

Pyroglutamyl-peptidase is able to specifically remove the amino-terminal pyroglutamyl residue protecting proteins or peptides from aminopeptidases. To clarify the mechanism of substrate recognition for the unique structure of the pyrrolidone ring, x-ray crystallography and site-directed mutagenesis were applied. The crystal structure of pyroglutamyl-peptidase bound to a transition state analog inhibitor (Inh), pyroglutaminal, was determined. Two hydrogen bonds were located between the main chain of the enzyme and the inhibitor (71:O⅐⅐⅐H-N:Inh and Gln71:N-H⅐⅐⅐OE:Inh), and the pyrrolidone ring of the inhibitor was inserted into the hydrophobic pocket composed of Phe-10, Phe-13, Thr-45, Ile-92, Phe-142, and Val-143. To study in detail the hydrophobic pocket, Phe-10, Phe-13, and Phe-142 were selected for mutation experiments. The k cat value of the F10Y mutant decreased, but the two phenylalanine mutants F13Y and F142Y did not exhibit significant changes in kinetic parameters compared with the wild-type enzyme. The catalytic efficiencies (k cat /K m ) for the F13A and F142A mutants were less than 1000-fold that of the wild-type enzyme. The x-ray crystallographic study of the F142A mutant showed no significant change except for a minor one in the hydrophobic pocket compared with the wild type. These findings indicate that the molecular recognition of pyroglutamic acid is achieved through two hydrogen bonds and an insertion in the hydrophobic pocket. In the pocket, Phe-10 is more important to the hydrophobic interaction than is Phe-142, and furthermore Phe-13 serves as an "induced fit" mechanism.

show abstract

Oxidation of Alcohols with o-Iodoxybenzoic Acid in DMSO: A New Insight into an Old Hypervalent Iodine Reagent

Cited by 362 publications

References 0 publications

Toward General Access to the <i>Aspidosperma</i>-Type Terpenoid Indole Alkaloids: Synthesis of the Key 3,3-Disubstituted Piperidones through Enantioselective Intramolecular Heck-Type Reaction of Chloroformamides

Toward General Access to the <i>Aspidosperma</i>-Type Terpenoid Indole Alkaloids: Synthesis of the Key 3,3-Disubstituted Piperidones through Enantioselective Intramolecular Heck-Type Reaction of Chloroformamides

First synthesis and oxidative properties of polymer-supported IBX

The Mechanism of Substrate Recognition of Pyroglutamyl-peptidase I from Bacillus amyloliquefaciens as Determined by X-ray Crystallography and Site-directed Mutagenesis

Contact Info

Product

Resources

About