Novel and Efficient Method for the Allylation of Carbonyl Compounds and Imines Using Triallylaluminum

Alkylarylation of styrenes via direct C(sp3)–Br/C(sp2)–H functionalization mediated by photoredox and copper cooperative catalysis

For straightforward access to various substituted 1,1-diarylalkanes a photoredox-catalyzed and copper-promoted 1,2-alkylarylation reaction of styrenes has been developed, which uses α-carbonyl alkyl bromides and N,N-disubstituted anilines as functionalization reagents.

Tertiary α-diarylmethylamines derived from diarylketimines and organomagnesium reagents

Organomagnesium reagents enable swift and versatile derivatisation of diarylimines to the corresponding α-substituted diarylmethylamines in excellent yields, through fast and clean reactions.

Cooperative titanocene and phosphine catalysis: accelerated C-X activation for the generation of reactive organometallics

The study presented herein describes a reductive transmetalation approach toward the generation of Grignard and organozinc reagents mediated by a titanocene catalyst. This method enables the metalation of functionalized substrates without loss of functional group compatibility. Allyl zinc reagents and allyl, vinyl, and alkyl Grignard reagents were generated in situ and used in the addition to carbonyl substrates to provide the corresponding carbinols in yields up to 99%. It was discovered that phosphine ligands effectively accelerate the reductive transmetalation event to enable the metalation of C-X bonds at temperatures as low as -40 °C. Performing the reactions in the presence of chiral diamines and amino alcohols led to the enantioselective allylation of aldehydes.

An Efficient Three-Component Synthesis of Homoallylic Amines Catalysed by MgI2 etherate

A three-component reaction of aldehydes, amines and allyltributylstannane was efficiently carried out to afford the corresponding homoallylic amine derivatives in the presence of 20 mol% of MgI2 etherate [(MgI2*(OEt2) n] under mild and neutral reaction conditions in good to excellent yields.

Titanocene(III) chloride mediated radical induced allylation of aldimines: formal synthesis of C-linked 4'-deoxy aza-disaccharide

Titanocene(III) chloride (Cp(2)TiCl) mediated radical induced allylation of aldimines for the preparation of homoallyl amines is described. The radical was generated from the allyl bromide using Cp(2)TiCl as the radical source. Formal synthesis of C(4)-C(5')-linked 4'-deoxy aza-disaccharide is demonstrated and a study toward the bicyclic skeleton of alkaloids was also accomplished. The radical initiator Cp(2)TiCl was prepared in situ from commercially available titanocene dichloride (Cp(2)TiCl(2)) and Zn dust in THF under argon.

Indium-mediated Barbier-type Allylation Reaction in PEG400 and PEG400/H2O

A green method for the allylation of aldehydes with allyl bromide mediated by indium in polyethylene glycol 400 (PEG400) and PEG400/H2O is described. Aldehydes with different substituents afforded the corresponding homoallylic alcohols in good to excellent yields. Comparative studies show that water promoted this reaction in PEG 400.

Chemoselective allylation of ketones in ionic liquids containing sulfonate anions

The chemoselective addition of tetraallyltin to dialkyl, alkenyl-alkyl, and alkynyl-alkyl ketones can be performed with high yields in N-methyl-N-butylpyrrolidinium trifuoromethansulfonate (MBP-Tf). Other room temperature ionic liquids (RTILs) can also be successfully employed if some sulfonic acid is added. The reaction is very sensitive to the electronic properties of the substrate. Aryl alkyl ketones bearing electron-withdrawing substituents behave like dialkyl ketones and react promptly; on the contrary, electron-rich aryl alkyl ketones react sluggishly, which allows selective competitive allylation of dialkyl substrates to occur. The ionic liquid solvent can be easily recycled, which meets the green chemistry principles of selectivity and reuse of chemicals. NMR spectroscopic data support the formation of tin-triflate catalysts in situ.

Efficient three-component one-pot benzylation and allylation of aldehydes and amines for synthesis of homobenzylamines and homoallylamines

A highly efficient, three-component one-pot benzylation and allylation of aromatic and aliphatic aldehydes and amines affords the corresponding homobenzylamines and homoallylamines in good to excellent yield. The procedure is lauded by its simplicity and manipulability.