The synthetic potential of 5-bromo-1,1,1-trifluoro-4-methoxypent-3-en-2-one toward the catalyst-free synthesis of N-pyrrolyl(furanyl)-piperazines, 1,4-diazepanes, and 1,4-diazocanes through a telescoped protocol is reported. This threecomponent one-pot method provided 23 examples with high chemo-and regioselectivity at yields up to 96%.

5-Bromo- and 5,5-dibromo-1,1,1-trihalo-4-methoxypent-3-en-2-ones (brominated enones) have proven to be attractive building blocks for the construction of heterocyclic and polyheterocyclic compounds bearing a trihalomethyl moiety through interesting cyclocondensation, alkylation, and cycloaddition reactions. This review compiles all of the reactions conducted with these brominated enones since they were first disclosed in 2001.1 Introduction2 Synthesis and Initial Applications3 Synthesis Using First-Generation Intermediates4 Synthesis Using Second-Generation Intermediates5 Synthesis Using Third-Generation Intermediates6 Conclusions

The simple preparation and functionalization of oxa/aza heterocycles requires new and efficient starting materials to be discovered so that regioselective methodologies with a wide range of applications in organic synthesis can be developed. With this in mind, β‐enamino diketones have emerged as a suitable building block for preparing the most diverse (poly)heterocyclic systems, through cyclocondensation or cycloaddition reactions. This review compiles all the reactions that have been conducted using these starting materials, ever since they were first disclosed in 1980.

This review describes advances in the synthesis of heterocyclic scaffolds (associated with their biological activity), using haloacetylated enol ethers as precursors. The wide variety of heterocycles that can be prepared using these precursors, together with the high regioselectivity they usually provide, in [3+2] and [3+3] cyclocondensation reactions, make these starting materials powerful tools. The biological evaluation is also highlighted, given that several analogues of commercially available drugs can be easily accessed.

Several commercially available lipases were examined in a study on O–Si bond formation and cleavage applying silicon-based protecting groups and alcohols or the corresponding silyl ethers. With regard to deprotection, from silyl ether to the corresponding alcohol, only the solvent and the lipase were necessary. The influence of the protecting group, the lipase source, and the substituent was investigated to optimize the results. The TMS moiety could be removed in 24 hours of reaction at room temperature in aqueous systems (conv. up to 99%, depending on the substrate and lipase). The reverse reactions, that is, with the protection of the alcohols, were carried out in hexane using different silyl chlorides. The TMS, TES, and TBS moieties were successfully inserted in the primary and secondary alcohols without the need for dry conditions or an inert atmosphere, presenting conversions of up to 99%, depending on the substrate.

The use of β-enamino diketones as an easy entry to the regioselective synthesis of [1,2,4]triazolo[1,5-a]pyrimidines is reported. These ketones reacted with 3-amino-1H-1,2,4-triazoles to furnish exclusively 6-substituted 5-(trifluoromethyl)[1,2,4]triazolo[1,5-a]pyrimidines in yields of up to 95%. The regioselectivity of the reactions performed was maintained regardless of the substituent in the starting ketone or aminoazole.

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