Mechanism of ester formation during decarboxylation with t-butyl hypochlorite and iodine

Abstract

Esters are formed from carboxylic acids and alkyl iodides upon treatment with t-butyl hypochlorite and iodine in carbon tetrachloride. Evidence is presented for a heterolytic mechanism whereby the iodine in the alkyl halide is replaced by the acyloxy-group of the acyl hypoiodite in the presence of iodine monochloride.

Visible‐Light Hypervalent Iodide Carboxylate Photo(trifluoro)methylations and Controlled Radical Polymerization of Fluorinated Alkenes

“…CX 3 COOI (quantitatively obtained from fast, dark, room-temperature reactions of I 2 [24][25][26][27][28][29][30][31][32]42] or R alk -I [43,44] with IDAB or IFAB) affects aromatic iodinations, [24][25][26] alkene iodoacetoxylations, [42] and may oxidize R alk I to CX 3 COOR alk . [43,44] However, while R Alk,Ar CH 2 COOI hypoiodides are stable in the dark, [44] the weak O À I bond, [40] and strong COOI chromophore [44] enable efficient visible light photolysis, [29,30,42,44] where the R-independent rate-determining O-I homolysis, followed by fast decarboxylation [27,39] and I 2 trapping, provides R alk I [27,28,32] within a solvent cage. [44] Consequently, RCOOIs mediate photohalodecarboxylative Hunsdieker-like HVIC reactions with R-I [43,45] or I 2 , [24-28, 32, 44] which have not yet been used in TFMs or polymerizations.…”

Visible‐Light Hypervalent Iodide Carboxylate Photo(trifluoro)methylations and Controlled Radical Polymerization of Fluorinated Alkenes

“…(4d) and (6)]. Therefore, CX 3 I formed faster44 and accumulated before CX 3 . slowly38 photoreleased from the remaining HVIC, begun initiating VDF.…”

“…CX 3 COOI (quantitatively obtained from fast, dark, room‐temperature reactions of I 2 24–32, 42 or R alk ‐I43, 44 with IDAB or IFAB) affects aromatic iodinations,24–26 alkene iodoacetoxylations,42 and may oxidize R alk I to CX 3 COOR alk 43. 44 However, while R Alk,Ar CH 2 COOI hypoiodides are stable in the dark,44 the weak OI bond,40 and strong COOI chromophore44 enable efficient visible light photolysis,29, 30, 42, 44 where the R‐independent rate‐determining O‐I homolysis, followed by fast decarboxylation27, 39 and I 2 trapping, provides R alk I27, 28, 32 within a solvent cage 44. Consequently, RCOOIs mediate photohalodecarboxylative Hunsdieker‐like HVIC reactions with R‐I43, 45 or I 2 ,24–28, 32, 44 which have not yet been used in TFMs or polymerizations.…”

“…This indicates that all I 2 was rapidly depleted in a fast HVIC24–32, 42 reaction [Eqs. (5) and (5′)], where the resulting CX 3 COOI was subsequently consumed by photo‐27–32, 44 and CX 3 . induced decarboxylation to CX 3 I [Eqs.…”

In situ formed tert-butyl hypoiodite as an efficient oxidant for rapid, room temperature, metal-free aromatization of Biginelli 3,4-dihydropyrimidin-2(1H)-ones under basic conditions

“…38 For example, Barton used this species to prepare N-iodoamides 39 and to decarboxylate carboxylic acids. 40 Other authors have used it in the preparation of esters from carboxylic acids and alkyl iodides, 41 and in the iodination of aromatics with strong electron donor substituents. The usual literature method for the preparation of tert-butyl hypoiodite is the reaction of tert-butyl hypochlorite with either molecular iodine or metal iodides, or by the reaction of potassium tert-butoxide with molecular iodine.…”