Francesco Minisci

Bio: Francesco Minisci is an academic researcher from Polytechnic University of Milan. The author has contributed to research in topics: Homolysis & Radical. The author has an hindex of 42, co-authored 241 publications receiving 6183 citations. Previous affiliations of Francesco Minisci include Polimeri Europa & Instituto Politécnico Nacional.

Recent developments of free-radical substitutions of heteroaromatic bases

Abstract: k R I + A r . * R. + A r I . k>109 M-~s ' (18) A l t h o x h ba th r e a c t i o n s gave good r e s u l t s i n many cases (Table 8), some l i m i t a t i o n s a re encountered wi th both r a d i c a l sources . Aroyl peroxides do r e a c t wi th t a l k p l iod ides , hu t do not produce t a l k y l rad i c a l s due t o i n compet i t ive i o n i c r e a c t i o n s . Moreover t h e thermal o r induced decomposition of a r o y l peroxides a t f i r s t produce aroyloxy r a d i c a l s , A r C O O , which r e a c t wi th s e v e r a l s u b s t r a t e s ( a c t i v a t e d aromatics, o l e f i n s , a lcohols , e t h e r s , amines) i n s t e a d o f gene ra t ing a r y l r a d i c a l s by decarboxyla t ion. HETEROCYCLES, Vol 28, No 1, 1989 The main limitation encountered with diazonium salts is due to the high addition rates of the nucleophilic radicals to the diazonium group, leading to the "free-radical diazo-coupling reaction" 27 (eq. 19). This competition can be in part restricted by keeping low the stationary concentration of the diazonium salt during the reaction. TABLE 8 Alkylation of heteroaromatic bases by diazonium salt, benzoyl peroxide and alkyl iodides 11 Heteroaromatic base Radical source Alkyl iodide Orientation Yield % a )

Activation of c-h bonds by metal complexes

Abstract: ion. The oxidative addition mechanism was originally proposed22i because of the lack of a strong rate dependence on polar factors and on the acidity of the medium. Later, however, the electrophilic substitution mechanism also was proposed. Recently, the oxidative addition mechanism was confirmed by investigations into the decomposition and protonolysis of alkylplatinum complexes, which are the reverse of alkane activation. There are two routes which operate in the decomposition of the dimethylplatinum(IV) complex Cs2Pt(CH3)2Cl4. The first route leads to chloride-induced reductive elimination and produces methyl chloride and methane. The second route leads to the formation of ethane. There is strong kinetic evidence that the ethane is produced by the decomposition of an ethylhydridoplatinum(IV) complex formed from the initial dimethylplatinum(IV) complex. In D2O-DCl, the ethane which is formed contains several D atoms and has practically the same multiple exchange parameter and distribution as does an ethane which has undergone platinum(II)-catalyzed H-D exchange with D2O. Moreover, ethyl chloride is formed competitively with H-D exchange in the presence of platinum(IV). From the principle of microscopic reversibility it follows that the same ethylhydridoplatinum(IV) complex is the intermediate in the reaction of ethane with platinum(II). Important results were obtained by Labinger and Bercaw62c in the investigation of the protonolysis mechanism of several alkylplatinum(II) complexes at low temperatures. These reactions are important because they could model the microscopic reverse of C-H activation by platinum(II) complexes. Alkylhydridoplatinum(IV) complexes were observed as intermediates in certain cases, such as when the complex (tmeda)Pt(CH2Ph)Cl or (tmeda)PtMe2 (tmeda ) N,N,N′,N′-tetramethylenediamine) was treated with HCl in CD2Cl2 or CD3OD, respectively. In some cases H-D exchange took place between the methyl groups on platinum and the, CD3OD prior to methane loss. On the basis of the kinetic results, a common mechanism was proposed to operate in all the reactions: (1) protonation of Pt(II) to generate an alkylhydridoplatinum(IV) intermediate, (2) dissociation of solvent or chloride to generate a cationic, fivecoordinate platinum(IV) species, (3) reductive C-H bond formation, producing a platinum(II) alkane σ-complex, and (4) loss of the alkane either through an associative or dissociative substitution pathway. These results implicate the presence of both alkane σ-complexes and alkylhydridoplatinum(IV) complexes as intermediates in the Pt(II)-induced C-H activation reactions. Thus, the first step in the alkane activation reaction is formation of a σ-complex with the alkane, which then undergoes oxidative addition to produce an alkylhydrido complex. Reversible interconversion of these intermediates, together with reversible deprotonation of the alkylhydridoplatinum(IV) complexes, leads to multiple H-D exchange

C-H bond functionalization: emerging synthetic tools for natural products and pharmaceuticals

Abstract: The direct functionalization of C-H bonds in organic compounds has recently emerged as a powerful and ideal method for the formation of carbon-carbon and carbon-heteroatom bonds. This Review provides an overview of C-H bond functionalization strategies for the rapid synthesis of biologically active compounds such as natural products and pharmaceutical targets.

Synthetic Organic Electrochemical Methods Since 2000: On the Verge of a Renaissance

Abstract: Electrochemistry represents one of the most intimate ways of interacting with molecules. This review discusses advances in synthetic organic electrochemistry since 2000. Enabling methods and synthetic applications are analyzed alongside innate advantages as well as future challenges of electroorganic chemistry.