Roberto Margarita

Asymmetric carbolithiation of 2-phenylselenofumarate derivatives: a short synthesis of (−)-roccellaric acid

Abstract (−)-Roccellaric acid and variously substituted succinates are obtained through direct asymmetric carbolithiation of 2-phenylselenofumarate derivatives, followed by reaction with suitable electrophiles.

Radical Additions to Olefins in the Presence of Iodobenzenediacetate: an Easy Route to Alkyl Dithiocyanates

Abstract We describe a new application of iodobenzenediacetate (IBDA), which is able to oxidize thiocyanate anion to the corresponding radical. Subsequent addition to nucleophilic olefins leads to dithiocyanate derivatives. The radical addition to olefins is more effective when performing the thiocyanation reaction in presence of Mg(ClO 4 ) 2 or TEMPO.

The binary reagent PhI(OAc)2-Mg(CIO4)2:a SET induced ring enlargement of furan derivatives into pyranones

Abstract The binary reagent PhI(OAc) 2 -Mg(CIO 4 ) 2 is very efficient for a high conversion of (2-furyl)-1-alcohols into pyranones. The reaction mechanism can be explained in terms of a SET process, with the generation of a cation radical as key intermediate.

Hypervalent iodine chemistry: Novel and direct thiocyanation of alkenes using [bis(acetoxy)iodo]benzene/trimethylsilyl isothiocyanate reagent combination. Synthesis of 1,2-dithiocyanates

Abstract Novel and direct thiocyanation of alkenes using [bis(acetoxy)iodo]benzene/trimethylsilyl isothiocyanate reagent combination has been developed.

Direct amino-phenylselenylation of enoates: An easy route to α-phenylseleno-β-amino esters and β-lactams

Abstract A “one-pot” procedure to obtain α-phenylseleno-β-amino esters from the corresponding enoates is described. The target compounds are useful synthetic tools and direct precursors of new α-phenylseleno-β-lactams, which can be easily transformed into their α-alkylidene analogues. A direct procedure to obtain α-phenylseleno-β-amino esters from the corresponding enoates is described. The target compounds are direct precursors of new α-phenylseleno-β-lactams. Download : Download full-size image

SELENIUM-DIRECTED CONJUGATE ADDITION OF AMINES TO DIMETHYL 2-PHENYLSELENO FUMARATE : REGIO AND DIASTEREOSELECTIVE SYNTHESIS OF 2-PHENYLSELENO-3-AMINO SUCCINATES

Abstract Dimethyl 2-phenylseleno fumarate 1 acts as a strong Michael acceptor of amines, providing the corresponding 2-phenylseleno-3-amino succinates 2a and 2b in very high yields with complete regio- and good diastereoselectivity.

Hypervalent iodine induced nucleophilic additions to alkenes: Synthesis of 1,2-diperchlorates

Abstract a novel iodine (III) reagent has been developed by the BAIB/Mg(ClO 4 ) 2 reagent combination. Reaction of this reagent with alkenes yielded 1,2-diperchlorates.

Reactions of 2,5-dihydro-2,5-dimethoxy-furan with phenylselenenylchloride: Regio- and stereocontrolled generation of highly functionalized C4 building-blocks

Abstract An efficient protocol for stereo- and regiocontrolled synthesis of small polyfunctional molecules is presented. The stereospecific addition of PhSeCl to 2,5-dihydro-2,5-dimethoxy-furan 1 in solvents, such as methylene chloride and methanol, gives cyclic and linear acetals 2 and 3, depending on the solvent used. Emphasis is given to the regiocontrolled hydrolysis of acetal groups for the preparation of stereodefined and highly functionalized C4 synthons, such as 8, 9 and 13.

Electrophilic assistance for cross-coupling reactions: A simple sythesis of mixed allylic ethers

Abstract Magnesium perchlorate, acting as a mild Lewis acid, is an efficient reagent for the synthesis of unsymmetrical ethers from allylic alcohols.

Hypervalent iodine-induced oxidative nucleophilic additions toalkenes: a novel acetoxy thiocyanation reaction in1,1,1,3,3,3-hexafluoropropan-2-ol

The combination of [bis(acetoxy)iodo]benzene and thiocyanate anion in a polar, protic non nucleophilic solvent such as 1,1,1,3,3,3-hexafluoropropan-2-ol is able to perform an oxidative nucleophilic addition to alkenes, leading to acetoxy thiocyanate derivatives, stereoselectively and with good regioselectivity.