Jacques Goré

Synthesis of Allylic Amines Through the Palladium- Catalyzed Hydroamination of Allenes.

The palladium-catalyzed addition of amines to allenes in the presence of triethylammonium iodide leads to allylic amines.

Palladium(II)-catalyzed formation of γ-butyrolactones from 4-trimethylsilyl-3-alkyn-1-ols: Synthetic and mechanistic aspects

Abstract γ-butyrolactones are obtained in good yields from 4-trimethylsilyl-3-alkyn-1-ols via Wacker-type oxidation reaction. A mechanism is proposed for this transformation: it involves two successive trans-hydroxypalladations followed by a [PdXSiMe3] syn-elimination and explains why the presence of the silyl group is essential in such a process.

Palladium-catalyzed addition of malonate type compounds to allenes via a hydropalladation process

Abstract The palladium and base-catalyzed addition of malonates and acetylacetates to allenic hydrocarbons affords allylated dicarbonyl compounds. Results account likely for an unprecedented hydropalladation process of the allenic unit which leads to a π-allylpalladium intermediate.

Palladium-mediated intramolecular cyclization of substituted pentynoic acids. A new route to γ-arylidenebutyrolactones

Abstract Benzo-annulated enol lactones are obtained in good yields from pentyonic acids 3- or 5- substituted with an iodo-aryl moiety by palladium-catalyzed cyclization of their potassium carboxylates.

Total synthesis of (+)-goniodiol

Abstract Cytotoxic styryl lactone, (+)-goniodiol 1, was prepared in enantioenriched form (ee 92%) in 15 steps from the α-(α′-alkoxyallenic) alcohol 5.

A New Route to γ-Arylidenebutyrolactones via a tandem carbopalladation-heterocyclisation sequence: a formal synthesis of U-68,215

Abstract Benzo-annulated enol lactones are obtained in good yields from pentynoic acids 3- or 5-substituted with an iodo-aryl moiety by palladium-catalyzed cyclization of their potassium carboxylates. Using this approach, an efficient new route to U-68,215 is described.

Rearrangement of α-hydroxy imines to α-amino ketones: Mechanistic aspects and synthetic applications

Abstract In refluxing diglyme, rearrangement of α-hydroxy imines bearing diversely substituted allyl groups or a 3-trimethylsilylpropargyl group on the α-carbon to the nitrogen afforded in good yields α-amino ketones. Migration of allyl or 3-trimethylsilylallyl groups occured without allylic transposition in contrast to the 1-methylallyl group. In the 3 cases studied, the rearrangement of enantioenriched α-hydroxy imines took place with complete 1,2-chirality transfer. The rearrangement was applied to the preparation of (+)-1-benzyl-1-azaspiro[5.5]undecan-7-one, a precursor in the synthesis of (−)-perhydrohistrionicotoxin.

REACTION OF THE LITHIO-DERIVATIVE OF METHOXY ALLENE WITH SAMP-HYDRAZONES :ACCESS TO ENANTIOPURE 3-PYRROLINES

Abstract α-Lithio methoxy allene reacts with SAMP-hydrazones to give α-allenyl hydrazines 5 or 3-methoxy-3-pyrrolines 6 depending on the nature of the solvent. Both compounds have been obtained with d.e. ≥ 99 %. Hydrogenolysis of the NN bond of 6 affords the pyrroline 7 in enantiopure form.

Reaction of the lithio-derivative of methoxyallene with hydrazones. Part 1: Synthesis and transformation of α-allenyl hydrazines ☆

Abstract The lithio-derivative of methoxyallene reacts with aldehyde hydrazones leading to expected α-allenyl hydrazines when ether is the solvent of the reaction. The yields are good as well as the diastereoselectivity observed in the case of SAMP-hydrazones. These hydrazines are cleanly transformed to N-dialkylamino-3-methoxy-3-pyrrolines when they are reacted with n-BuLi in THF. These compounds are sometimes accompanied by the isomeric 4-methyl azetidines. The N-dialkylamino-3-methoxy-3-pyrrolines are transformed to 3-methoxy-3-pyrrolines by hydrogenolysis of the nitrogen–nitrogen bond, to 3-alkoxy-pyrroles by treatment with a peracid and to 3-amino-pyrroles by acidic migration of the dialkylamino group. In the case of SAMP-hydrazines, the obtained 3-methoxy-3-pyrrolines have a high enantiomeric purity. Lastly, attempts to prepare α-hydrazino-esters (and subsequently α-amino-esters) by ozonolysis of the allenyl moiety failed due to the formation of a methyl glyoxylate.

Thermal rearrangement of enantioenriched α-hydroxy imines -I. Enantiocontrolled synthesis of α-substituted α-amino ketones

Abstract Enantioenriched 2-allyl- and 2-(3-trimethylsilylpropargyl)-2-hydroxycyclohexanone were respectively obtained by resolution from the corresponding diastereomeric acetal derived from C2-symmetrical diol or from the camphanate ester. Study of the rearrangement of their corresponding imine derivatives has shown that it occurred with complete retention of the stereogenicity.