Phenylsilane as been reassed as useful coupling reagent for amides synthesis. Peptides and Weinreb amides are easily obtained under mild conditions in absence of epimzerization even with challenging substrates such as phenylglycine. Further investigation regarding the reactivity of stable acetoxysilanes supported phenylpolyacyloxysilane as key intermediate.
Chemoselective Intermolecular Cross-Enolate-Type Coupling of Amides
作者:Daniel Kaiser、Christopher J. Teskey、Pauline Adler、Nuno Maulide
DOI:10.1021/jacs.7b08813
日期:2017.11.15
A new approach for the synthesis of 1,4-dicarbonyl compounds is reported. Chemoselective activation of amide carbonyl functionality and subsequent umpolung viaN-oxide addition generates an electrophilic enolonium species that can be coupled with a wide range of nucleophilic enolates. The method conveys broad functional group tolerance on both components, does not suffer from formation of homocoupling
The use of readily available hydroxamic acids as reagents for the chemoselective (ortho‐amino)arylation of amides is described. This reaction proceeds under metal‐free, mild conditions, displays a very broad scope, and constitutes a direct approach for the metal‐free attachment of aniline residues to carbonyl derivatives.
Rhodium(III)‐Catalyzed Synthesis of Skipped Enynes via C(sp
<sup>3</sup>
)–H Alkynylation of Terminal Alkenes
作者:Franco Della‐Felice、Margherita Zanini、Xiaoming Jie、Eric Tan、Antonio M. Echavarren
DOI:10.1002/anie.202014877
日期:2021.3.8
The RhIII‐catalyzedallylicC−H alkynylation of non‐activated terminalalkenes leads selectively to linear 1,4‐enynes at room‐temperature. The catalytic system tolerates a wide range of functional groups without competing functionalization at other positions. Similarly, the vinylic C−H alkynylation of α,β‐ and β,γ‐ unsaturated amides gives conjugated Z‐1,3‐enynes and E‐enediynes.
We developed a new transition-metal-free intermolecular Claisenrearrangement process to introduce allyl and allenyl groups into the α position of tertiary amides. In this transformation, amides were activated by trifluoromethanesulfonic anhydride to produce the keteniminium ion intermediates that exhibit strong electrophilic activity. This atom-economical process delivers α position-modified amides