Search

Indium‐mediated allylation of N‐tert‐butanesulfinyl imines derived from indole‐2 and 3‐carbaldehydes 3 and 5 with allylic bromides 6, proceed with high diastereoselectivity. Homoallylic amide derivatives 13 and 14 are transformed into dihydropyridinones 15 and 16, upon successive desulfinylation, N‐acylation with acryloyl chloride and ring‐closing‐metathesis. Desulfinylation of amine ester derivatives 17 and 18, obtained when ethyl 2‐(bromomethyl)acrylate (6 b) is used as the allylating reagent, lead to the corresponding α‐methylene‐γ‐butyrolactams 19 and 20, in modest yields. [ABSTRACT FROM AUTHOR]

A simple methodology for the synthesis of N - tert -butanesulfinyl-α-keto aldimines from both α-keto aldehydes and carboxylic esters has been developed. The addition of an in situ formed allyl indium reagent to these chiral imines was also studied. The addition took place in a sequential manner, first to the imine group with excellent diastereoselectivity and then to the carbonyl group with lower diastereoselectivity. Ruthenium-catalyzed ring closing metathesis of the resulting 5-aminoocta-1,7-dien-4-ol derivatives provided access to 6-aminocyclohex-3-enols. Reduction of the α-keto aldimines led to N - tert -butanesulfinyl-1,2-aminoalcohols as a 1:1 diastereomeric mixture. [ABSTRACT FROM AUTHOR]

The palladium(ii)-catalyzed oxidation of homoallylic amine derivatives resulting from the allylation of N-tert-butanesulfinyl imines with allyl bromide led to the formation of the corresponding terminal allylic acetates in a regioselective fashion in moderate yields. In the case of the homoallylic amine derivatives obtained using cyclohexenyl bromide as the allylating reagent, the allylic oxidation took place with high regio- and diastereoselectivity and yields ranging from 40 to 85%. [ABSTRACT FROM AUTHOR]

The indium-mediated allylation of α-aldimino and -ketimino esters 3 with allylic bromides proceeds with high diastereoselectivity to yield homoallylic α-amino ester derivatives 5 , in both THF and water as solvents. The reactions are diastereospecific, the stereochemical outcome depending on the configuration of both the sulfur atom of the sulfinyl group and the C N double bond. Of particular interest are the reaction products using ethyl bromomethylacrylate as allylating reagent because amino diesters are obtained, which can be easily transformed into enantiomerically pure α-methylidene-γ-butyrolactams 6 with an alkoxycarbonyl group on the ring bearing the nitrogen atom. [ABSTRACT FROM AUTHOR]

The palladium-catalyzed allylation of N-tert-butanesulfinyl imines with allylic alcohols in the presence of InI as reducing reagent takes place with high diastereoselectivity in reasonable yields. The reaction with crotyl alcohol is totally regioselective, leading to the antidiastereomer as the main reaction product. [ABSTRACT FROM AUTHOR]

The indium-promoted allylation of enantiomerically pure N- tert-butylsulfinyl imines has been shown to be a versatile and useful methodology for the preparation of diastereomerically enriched N-protected homoallylamines. The preparation of both enantiomeric diastereomers is possible by changing the stereochemistry of the starting imine. Importantly, the deprotection of the sulfinylamines is easily achieved by acid treatment, and, therefore, the corresponding free amines are accessible in an enantioenriched manner. This methodology has been applied to the synthesis of interesting compounds, that is, mostly alkaloids and a wide representation of naturally occurring products. [ABSTRACT FROM AUTHOR]

Chiral tert-butylsulfinyl imines 3, which are easily prepared from the corresponding bromo carbonyl compounds 1 and tert-butanesulfinamide ( 2), undergo a diastereoselective allylation by using indium metal and allyl bromide to give the corresponding homoallyl sulfinylamines 4. Treatment of compounds 4 with a catalytic amount of palladium acetate and triphenylphosphane gives exo-methylene-substitutedsulfinylamino)benzocycloalkenes 5 (five- to seven-membered rings) that are easily deprotected with hydrochloric acid to give chiral primary amines 6. [ABSTRACT FROM AUTHOR]

Review: 35 refs. [ABSTRACT FROM AUTHOR]

The authors report on a two-step synthesis to the title cycloalkenes via an indium-promoted allylation reaction, followed by a Heck-coupling reaction. [ABSTRACT FROM AUTHOR]

The article highlights diastereoselective allylations which involve the use of chiral reagents. It further discusses the application of carbonyl compounds and imines to the synthesis of natural products. It reflects on the propargylation/allenylation processes, and the application of these methods to synthesis of natural products.

The article examines the literature of enantioselective catalyzed allylation of carbonyl compounds as well as the stereoselective allylation of imines. It notes that the developments in catalytic enantioselective allylation serve as the consequence of the organic chemists' efforts in improving the tool to come up with carbon-carbon bonds. It also remarks the significant progress in the atom economy of the global process and in the use of nontoxic allylic reagents.

A convenient protocol for the Pd-catalyzed allylation of chiral imines with allylic alcohols to afford the corresponding products with high diastereoselectivities is developed. [ABSTRACT FROM AUTHOR]