The Chemistry of Peresters

Abstract

Peresters have long been familiar as radical initiators, oxidants for allylic functionalization, and as sources of electrophilic oxygen. In recent years, peresters have emerged as important reagents or intermediates for many additional reactions or processes, including C-H activation, dehydrogenative coupling, and activation of transition metal catalysts. This compre

Synthesis of O-tert-Butyl-N,N-disubstituted Hydroxylamines by N–O Bond Formation

“…28 Moreover, derivatives can be easily accessed by standard acylation chemistry. 28 Nucleophilic addition to perester electrophiles can occur through two different pathways: (i) 1,2-addition at the carbonyl group and (ii) 1,4-addition to the peroxy oxygen. 28 Previous studies on the nucleophilic addition of amines to TBPB demonstrated that the C-attack (1,2-addition) predominates over the corresponding O-attack (1,4-addition).…”

“…The extrapolation of this method to hydroxylamine formation was attractive considering that TBPB is commercially available and employed in oxidations. 28 Moreover, derivatives can be easily accessed by standard acylation chemistry. 28 Nucleophilic addition to perester electrophiles can occur through two different pathways: (i) 1,2-addition at the carbonyl group and (ii) 1,4-addition to the peroxy oxygen.…”

“…28 Nucleophilic addition to perester electrophiles can occur through two different pathways: (i) 1,2-addition at the carbonyl group and (ii) 1,4-addition to the peroxy oxygen. 28 Previous studies on the nucleophilic addition of amines to TBPB demonstrated that the C-attack (1,2-addition) predominates over the corresponding O-attack (1,4-addition). For example, Bhanage reported 29 a mild benzoylation procedure wherein amines react chemoselectively with TBPB to afford benzamides in high yields.…”

“…Considering the major steric dependence noted by Benn 31 in the reaction of lithium amides with TBPB, we resorted to the time-honored strategy of employing ortho,ortho-disubstitution to impede 1,2-addition to the carbonyls. 35−38 Accordingly, we prepared tert-butyl 2,6-dimethyl perbenzoate by standard acylation chemistry 28 for further investigation (see the Supporting Information for more details).…”

Stereoselective Alkylation of Chiral Titanium(IV) Enolates with tert-Butyl Peresters

“… 15 Widely used phthalimide-derived esters 16 containing an O–N bond proved to be unreactive, but peresters containing an O–O bond turned out to be much more satisfactory. 17 Herein, we describe the chemo- and stereoselective Cα alkylation of titanium(IV) enolates from chiral N -acyl oxazolidinones with tert -butyl peresters from branched aliphatic carboxylic acids, which permits the stereocontrolled introduction of secondary and tertiary alkyl groups with moderate to high yields ( Scheme 1 ). Importantly, this method gives a straightforward access to enantiomerically pure intermediates that can be employed as precursors for ligands in catalytic and asymmetric synthesis.…”