Synthesis of Silicon Substituted Cyclopropylmethyl Alcohols in Optically Active Form <i>via</i> Asymmetric Simmons-Smith Reaction of γ-Silicon Substituted Allylic Alcohols

Ukaji, Yutaka; Sada, Kazunori; Inomata, Katsuhiko

doi:10.1246/cl.1993.1227

Cited by 53 publications

(18 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Hydroalumination of 22 followed by addition of iodine [40] and subsequent O-silylation under standard conditions furnished product 23. Lithium for halogen exchange triggered a retro-Brook rearrangement that installed the Csilyl substituent and released the primary alcohol in 24, [41] which was then oxidized to the corresponding acid 26 in excellent overall yield.…”

Section: Resultsmentioning

confidence: 99%

Total Synthesis and Biological Evaluation of the Cytotoxic Resin Glycosides Ipomoeassin A–F and Analogues

Nagano

Pospíšil

Chollet

et al. 2009

Chemistry A European J

View full text Add to dashboard Cite

A multitasking C-silylation strategy using the readily available compound 26 as a surrogate for cinnamic acid represents the key design element of a total synthesis of all known members of the ipomoeassin family of resin glyosides. This protecting group maneuver allows the unsaturated acids decorating the glucose subunit of the targets to be attached at an early phase of the synthesis, prevents their participation in the ruthenium-catalyzed ring-closing metathesis (RCM) used to form the macrocyclic ring, and protects them against reduction during the hydrogenation of the resulting cycloalkene over Wilkinson's catalyst. As the C-silyl group can be concomitantly removed with the O-TBS substituent using tris(dimethylamino)sulfonium difluorotrimethylsilicate (TASF) in acetonitrile, no separate protecting group manipulations were necessary in the final stages, thus contributing to a favorable overall "economy of steps". In addition to the naturally occurring ipomoeassins, a small set of synthetic analogues has also been prepared by "diverted total synthesis". The cytotoxicity of these compounds was assayed with two different cancer cell lines. The recorded data confirm previous findings that the acylation- and oxygenation pattern of these amphiphilic glycoconjugates is highly correlated with their biological activity profile. Ipomoeassin F turned out to be the most promising member of the series, showing IC(50) values in the low nanomolar range.

show abstract

Section: Resultsmentioning

confidence: 99%

Total Synthesis and Biological Evaluation of the Cytotoxic Resin Glycosides Ipomoeassin A–F and Analogues

Nagano

Pospíšil

Chollet

et al. 2009

Chemistry A European J

View full text Add to dashboard Cite

show abstract

“…In 1992, Ukaji et al. reported a highly enantioselective method by using diethyl tartrate as a stoichiometric chiral auxiliary 4a,c. 5 Denmark and Edwards reported an efficient method that included a chiral amino alcohol 4b.…”

Section: Asymmetric Simmons–smith Reactions Of 1 With Al(salalen) Commentioning

confidence: 99%

“…4, 9 When the substrate is an allylic alcohol, the alcohol or the resulting alkoxyzinc species forms an aggregate with the iodomethylzinc species and the chiral auxiliary, and subsequently undergoes an asymmetric Simmons–Smith reaction. The aggregate can occur in one of three different modes (Figure 1 a–c): a) capture of an allyloxy(iodomethyl)zinc species by a Lewis acid catalyst derived from the chiral auxiliary,8a, 11c b) capture of an allyloxyzinc and iodomethylzinc species by a bifunctional chiral auxiliary (in this case, the use of a C 2 ‐symmetric auxiliary like diethyl tartrate4a, c should be important for obtaining high enantioselectivity if the two species are captured by two identical groups), and c) capture of the two species by a Lewis acid/base bifunctional catalyst 12. Charette et al.…”

Section: Asymmetric Simmons–smith Reactions Of 1 With Al(salalen) Commentioning

confidence: 99%

Asymmetric Simmons–Smith Reaction of Allylic Alcohols with Al Lewis Acid/N Lewis Base Bifunctional Al(Salalen) Catalyst

Shitama

Katsuki

2008

Angewandte Chemie

View full text Add to dashboard Cite

show abstract

“…Hydroalumination of 22 followed by addition of iodine40 and subsequent O ‐silylation under standard conditions furnished product 23 . Lithium for halogen exchange triggered a retro‐Brook rearrangement that installed the C ‐silyl substituent and released the primary alcohol in 24 ,41 which was then oxidized to the corresponding acid 26 in excellent overall yield.…”

Section: Resultsmentioning

confidence: 99%

Bioactive Unnatural Somatostatin Analogues through Bioorthogonal Iodo‐ and Ethynyl‐Disulfide Intercalators

Pfisterer¹,

Eisele²,

Chen³

et al. 2011

Chemistry A European J

View full text Add to dashboard Cite

Iodo- and ethynyl-containing bisalkylating bioconjugation agents 5 and 8 were achieved and allow the introduction of reactive unnatural substituents into proteins and peptides whilst the bioactive 3D structure is retained. Derivatives of the peptide hormone somatostatin bearing a single iodo or ethynyl group were prepared through intercalation into the disulfide bridge. For the first time, the exact reaction mechanism of the intercalation was elucidated by applying 2D NMR experiments and it was shown that, during the reaction, somatostatin diastereomers were formed. Site-directed modification of the ethynyl-modified peptide with a coumarin chromophore was achieved through a [1,3] dipolar Huisgen cycloaddition reaction; this suggests that such a derivative could serve as an attractive platform to prepare artificial somatostatin compound libraries. The biological activity and specificity of a representative modified somatostatin derivative was demonstrated and efficient receptor-mediated cell uptake occurred in a dose-dependent manner into receptor positive cells only. The iodo and ethynyl bioconjugation reagents presented herein could be applied for introducing such substituents into alternative peptides and proteins and, in principle, could facilitate the efficient design of a broad variety of artificial protein and peptide analogues with previously unknown bioactivities.

show abstract

Synthesis of Silicon Substituted Cyclopropylmethyl Alcohols in Optically Active Form via Asymmetric Simmons-Smith Reaction of γ-Silicon Substituted Allylic Alcohols

Cited by 53 publications

References 10 publications

Total Synthesis and Biological Evaluation of the Cytotoxic Resin Glycosides Ipomoeassin A–F and Analogues

Total Synthesis and Biological Evaluation of the Cytotoxic Resin Glycosides Ipomoeassin A–F and Analogues

Asymmetric Simmons–Smith Reaction of Allylic Alcohols with Al Lewis Acid/N Lewis Base Bifunctional Al(Salalen) Catalyst

Bioactive Unnatural Somatostatin Analogues through Bioorthogonal Iodo‐ and Ethynyl‐Disulfide Intercalators

Contact Info

Product

Resources

About