A novel ynamide preactivation strategy enables the use of otherwise incompatible reagents and allows preparation of α,β-disubstituted enamides with high regio- and stereoselectivity. Mechanistic analysis reveals the intermediacy of a triflate-bound intermediate as a solution-stable, effective keteniminium reservoir, whilst still allowing subsequent addition of organometallic reagents.

No abstract

Selenoesters are compounds of great synthetic relevance since they can be used in several types of chemical transformations and mainly due to their great capacity in the formation of acyl radicals. Therefore, the scientific community has been developing several methods for the synthesis of this class of molecules. This review will address the synthesis of these compounds from different starting materials, such as carboxylic acids derivatives (acid chlorides and anhydrides), aldehydes, selenoacetylenes and miscellaneous methods.

The copper-catalyzed hydroboration of selenoalkynes in a regio- and stereoselective fashion is reported, delivering selenium-containing vinylboronate products in good yields. The reported protocol fills an important gap in the literature...

Herein, we report our studies on the synthesis of vinyl 1,2,3-triazoles through a one-pot sequence, enabled by the same copper catalyst, of three different reactions: hydroboration involving an alkyne, azidation for a vinyl boronate and azide–alkyne cycloaddition.

An approach for the mild synthesis of selenoesters starting from selenoalkynes through an acid-catalyzed, redox-neutral oxyarylation reaction is reported. Brønsted acid activation of a selenoalkyne leads to a selenium-stabilized vinyl cation, which is captured by an aryl sulfoxide and undergoes sigmatropic rearrangement to deliver the final α-arylated selenoester product. Computational studies have been carried out to elucidate the nature of the Se-stabilized carbocation.

A new approach to prepare α-selanyl-α,β-unsaturated thioesters from propargylthioalkynes and an electrophilic selenium species is reported. Pivotal is the intermediacy of a sulfur-stabilized vinyl cation, which is captured intramolecularly and...

No abstract