Transfer-alkylation

Studying alkylations, we developed a series of selective ionic alkylating agents. Although Meerwein s trialkyloxonium and dialkoxycar-benium salts are widely used as transfer alkylating agents, they lack selectivity and generally are incapable of C-alkylation. 

Addition to Carbonyl Compounds. Unlike Grignard and alkykitliium compounds, trialkylboranes are inert to carbonyl compounds. The air-catalyzed addition to formaldehyde is exceptional (373). Alkylborates are more reactive and can transfer alkyl groups to acyl halides. The reaction provides a highly chemoselective method for the synthesis of ketones (374). 

Perbenzoic acid, m-chloro- [Benzenecar-boperoxoic acid, 3-chloro-J, 55, 88 PHASE TRANSFER ALKYLATION, 55, 91 PHASE TRANSFER CATALYSIS, 55, 96 Phenol, thio- [Benzenethiol], 55, 122 Phenol, 2,4,6 tnbromo-, 55, 20 m-Phcnylenediamine [1,3 Benzenediamine], p-bromination of, 55, 23 Phosphine, phenyl-, bis(3-dimethylamino-... 

Aluminum alkyls also undergo reactions in which they function by transferring alkyl groups. 

In terms of their chemical behavior, dialkylzinc compounds generally react to transfer alkyl groups to other metals. Dialkyls of cadmium are usually prepared by the reaction of a Grignard reagent with a cadmium halide. 

K. Manabe, Asymmetric Phase-Transfer Alkylation Catalyzed by a Chiral Quaternary Phosphonium Salt with a Multiple Hydrogen-Bonding Site , Tetrahedron Lett. 1998, 39, 5807-5810. 

K. Manabe, Synthesis of Nobel Chiral Quaternary Phosphonium Salts with a Multiple Hydrogen-Bonding Site, and Their Application to Asymmetric Phase-Transfer Alkylation , Tetrahedron 1998, 54, 14465-14476. 

J. J. Eddine, M. Cherqaoui, Chiral Quaternary Benzo-phenone Hydrazonium Salt Derivatives Efficient Chiral Catalysts for the Enantioselective Phase-Transfer Alkylation of Imines. Application to Synthesis of Chiral Primary Amines , Tetrahedron Asymmetry 1995, 6, 1225-1228. 

Transferring alkyl or aryl groups, other 3.1.13 Exoribonucleases producing 5 -phospho-... 

Modifications in the benzyl portion of the molecule are significant. The nitro group in the benzyl portion of the molecule apparently increases the local polarity of the transition state. The influence on the chemical and enantiomeric yield of variations in the benzyl portion of the quininium salt was dramatically confirmed recently by the work of Dolling and coworkers on the phase-transfer alkylation of a hydrindanone (83). 

The first example of a chiral carbanionic residual ligand has recently been reported [238]. Chiral mixed cuprates generated from alkyllithium reagents and cyclic a-sulfonimidoyl carbanions transfer alkyl ligands [such as n-Bu, Me, (CH2)30CH(Me)0Etj to cyclic enones with excellent enantioselectivities (77-99% ee). 

C. Lemaire, S. Gillet, S. Guillouet, A. Plenevaux, J. Aerts, A. Luxen, Highly enantioselective synthesis of no-carrier-added 6-[ F]fluoro-L-DOPA by chiral phase-transfer alkylation, Eur. J. Org. Chem. 13 (2004) 2899-2904. 

Transferases that Transfer Alkyl or Aryl Groups, Other than Methyl Groups (EC 2.5.)... 43... 

This review focuses on acyl- and glycosyltransferases and transferases that transfer alkyl or aryl groups, other than methyl groups (EC 2.3, EC 2.4, and EC 2.5) as in these classes can be found interesting examples for the polymer scientist. 

Phase-transfer alkylation has been utilized in the preparation of 1-arylcyclobutanecarbonitriles starting from arylacetonitriles and 1,3-dihalopropanes.10... 

Pentynoic acid, 5-hydroxy-, 56, 51 2-Pcntynoic acid, methyl ester 55, 76 Peptides, 56, 88 Peracetic acid, 55, 87, 88 Perbenzoic acid, m-chloro-, 55, 88 Perbenzoic acid, 3-chloro-, 56, 1 Peroxydisulfunc acid ([(HO)S-(0)2 ] 2 Ot), diammomum salt, 56, 69 PHASE TRANSFER ALKYLATION, 55,... 

The main reactions of the MTG/MTO process can be summarized as follows the first is the dehydration of methanol to DME on acidic zeolite catalysts. The equilibrium mixture of methanol, DME, and water is then converted to light alkenes, which react further to form higher alkenes, n- and Ao-alkanes, aromatics, and naphthenes by hydrogen transfer, alkylation, polycondensation, isomerization, and other secondary reactions. 

The results reported in this section are in agreement with the general behavior of intermolecular phase-transfer alkylations. The best yields are obtained when five- and six-membered rings are prepared. 

---