Front Cover Picture: Regioselective [2+2+2] Cycloaddition Reaction Using Allene‐ynes with Simple Allenes under Nickel Catalysis (Adv. Synth. Catal. 21/2019)

Regioselective nickel-catalyzed reductive couplings of enones and allenes.

Catalytic reductive coupling processes have been developed in numerous contexts as a strategy for the regioand stereoselective installation of alkenes. The direct coupling of a polar p system with a relatively nonpolar p system is often a successful strategy for selectively accomplishing synthetically desirable heterocouplings while avoiding undesired homocoupling of either reagent. For example...

Exploiting [2+2] cycloaddition chemistry: achievements with allenes.

The allene moiety represents an excellent partner for the [2+2] cycloaddition with alkenes and alkynes, affording the cyclobutane and cyclobutene skeletons in a single step. This strategy has been widely studied under thermal, photochemical and microwave induced conditions. More recently, the use of transition metal catalysis has been introduced as an alternative relying on the activation of th...

PREPARATION OF (CHLOROCARBONYL) PHENYLKETENB AND ITS CYCLOADDITION REACTION WITH BENZALDEHYDEV

Meldrum's acid, 2'5-diphenyl-1'3-dioxane-4'6-dione, was produced by [2+2] cycloadditions of the (chlorocarbony1)phenylketene with benzaldehyde. Acid hydrolysis of the meldrum's acid regenerated benzaldehyde and also yielded phenylacetic acid as the final product

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Front Cover: Early‐Stage Incorporation Strategy for Regioselective Labeling of Peptides using the 2‐Cyanobenzothiazole/1,2‐Aminothiol Bioorthogonal Click Reaction (ChemistryOpen 3/2018)