ACYL MAIN GROUP METAL AND METALLOID DERIVATIVES IN ORGANIC SYNTHESIS. A REVIEW

Organobase-Catalyzed Umpolung of Amides: The Generation and Transfer of Carbamoyl Anion

A novel organobase-catalyzed umpolung reaction of amides was disclosed. This method provides an efficient method to generate and transfer carbamoyl anions. In this transformation, some of the inherent disadvantages of carbamoyl metal were avoided. The mechanistic analysis revealed that the reaction proceeds through polarity inversion of amide, and various carbamoyl anions were applied in the reaction. Moreover, a wide range of substrates was achieved with moderate to excellent yield.

Carbamoyl Anion Addition to Azirines

The addition of carbamoyl anions to azirines affords synthetically useful 2-aziridinyl amide building blocks. The reaction scope was explored with respect to both formamide and azirine, and the addition was found to be highly diastereoselective. A one-pot conversion of a ketoxime to an aziridinyl amide was demonstrated. The method was employed to incorporate an aziridine residue into a dipeptide segment.

Synthesis of α,β-Unsaturated Acylsilanes via Perrhenate-Catalyzed Meyer-Schuster Rearrangement of 1-Silylalkyn-3-ols

We report the synthesis of α,β-unsaturated acylsilanes via the perrhenate-catalyzed Meyer-Schuster rearrangement of 1-silylalkyn-3-ols. Propargylic alcohols derived from TES-acetylene and substituted benzaldehydes can be converted to acylsilanes using a combination of p-TSA·H(2)O and n-Bu(4)N·ReO(4), or Ph(3)SiOReO(3) in good yields. Some propargylic alcohols derived from ketones, as well as aliphatic and unsaturated aldehydes, can also be converted to acylsilanes; however, they were often prone to side reactions.

Functionalised organolithium compounds by sulfur-lithium exchange

Multifunctional organic molecules can be accessed by reacting functionalised organolithium compounds (they can be prepared following a great number of different methodologies) with electrophilic reagents, this fact makes these intermediates of relevant interest in synthetic organic chemistry. Sulfur containing molecules have been used extensively as precursors of organolithium compounds by applying two different methodologies. One is the well-known alpha-deprotonation, which is not going to be the subject of this review, and the other methodology consists of sulfur lithium exchange by using lithium metal either alone or in the presence of a stoichiometric or catalytic amount of an arene. In some special cases, for instance in gem-dithio- or 1,1,1-trithiosubstituted compounds, sulfur lithium exchange can be performed by means of an alkyllithium reagent. The following tutorial review is ordered on the basis of the relative position of the functional group and the carbanionic center, with special mention to the application of these intermediates in organic synthesis.

Synthesis of α, β-Unsaturated Tellurolesters by the Reaction of Acylzirconocene Chlorides with ArTeI

α, β-unsaturated tellurolesters have been prepared in good yield by the reaction of ArTeI with acylzirconocene chlorides.

Synthesis of α, β-Unsaturated Selenoesters by the Reaction of Acylzirconene Chlorides with ArSeBr

α, β-Unsaturated selenoesters are prepared in good yields by the reaction of ArSeBr with acylzirconene chlorides.