Tert-butyl iodide

Specifically, the reaction of trifluoromethyl radicals with carbon tetra-iodide produces perfluoro-tert-butyl iodide and perfluoroneopentane in the ratio of 3 1. Incomplete substitution is presumably due to steric factors around the crowded, central carbon atom. 

This simple view is clearly true for some reactions, e.g., the Diels-Alder dimerization of cyclopentadiene, where the rate constant in ethanol is the same as in hexane, and only a factor of three larger than in the gas phase. In contrast, for the example mentioned above of the 8 2 reaction (1), the reaction proceeds fifteen orders of magnitude faster in the gas phase than in methanol. For the Sfjl reaction of tert-butyl iodide, however, the gas phase rate constant can be estimated to be about 86 orders of magnitude slower than the solution phase rate constant. It is thus for ionic reactions that the tremendous changes in the rate constant upon solvation are seen. We are therefore specifically interested in those gas phase ion-molecule reactions that are the counterparts to the well-known solution phase reactions. 

The following Wlliamson ether synthesis is preferred. The alternate Wlliamson ether synthesis (the reaction between sodium ethoxide and tert-butyl iodide) would fail because dehydrohalogenation (that is, E2 elimination) would be faster than substitution. 

Ethyl- and methyldifluoramine have been prepared by reaction of the respective iodides with tetrafluorohydrazine excited by ultraviolet radiation (5). We therefore investigated the free radical reaction of tert-butyl iodide with tetrafluorohydrazine and found that it produced the desired tert-butyldifluoramine routinely in 40% yield. The reaction is believed to take place by the following steps ... 

In 1995, Porter et al. [34] reported the first excellent results for free radical addition to an electron-deficient alkene by use of chiral zinc complexes. Reaction of the oxa-zolidinone 9 with tert-butyl iodide and allyltributylstannane 30 in the presence of Zn(OTf)2 and a chiral bis(oxazoline) ligand 12 gave the adduct 44 in 92 % yield with 90 % ee (Sch. 18). The chiral bis(oxazoline) complexes derived from ZnCl2 or Mg(OTf)2 gave racemic products. In this reaction, lower allyltin/alkene ratios gave substantially more telomeric products, and a [3 + 2] adduct 45 of the oxazolidinone 9 and the allylstannane 30 was obtained at temperatures above 0 °C. 

C4F9I perfluoro-tert-butyl iodide 4459-18-1 25.00 2.1157 2 2567 C4H4N20S 2,3-dihydro-2-thioxo-4(1H)-pyrimidinone 141-90-2 25.00 1.3676 2... 

Remarkably coincident experimental values for A H° 6) can be obtained from (1) PEPICO studies on tert-butyl iodide " (2) appearance energies for the formation of 6 from isobutane, neopentane and tert-butyl iodide (threshold... 

Treatment of a-iodo ketone and aldehyde with an equimolar amount of Et3B yielded the Reformatsky type adduct in the absence of PhaSnH (Scheme 21), unlike ot-bromo ketone as shown in Scheme 15 [22], Ethyl radical abstracts iodine to pro-duee carbonylmethyl radical, which would be trapped by EtsB to give the corresponding boron enolate and regenerate an ethyl radical. The boron enolate reacts with aldehyde to afford the adduct. The three-component coupling reaction of tert-butyl iodide, methyl vinyl ketone and benzaldehyde proceeded to give the corresponding adduct 38, with contamination by the ethyl radical addition product 39. The order of stability of carbon-centered radical is carbonylmethyl radical > Bu > Pr > Ef > Me . 

This free-radical acylation approach is extended for the synthesis of a-keto esters and ketones using phenylsulfonyl methoxycarbonyl oxime ether 5 [23] and bis-methanesulfonyl oxime ether 6, respectively (Scheme 6) [24], 5 is more reactive and effective than 2b. For instance, radical reaction of tert-butyl iodide with 5 gave tert-butyl oxime ester in 65% yield, whereas the use of 2b gave the corresponding tert-butyl oxime ether in 15% yield. In free-radical-mediated ketone synthesis via a sequential radical acylation approach, 6 is used as a carbonyl equivalent geminal radical acceptor. This method works well with primary alkyl iodides but somewhat less efficiently with secondary iodides and can be applied to prepare unsymmetrical acyclic ketones as well as cyclic ketones. It is noteworthy that stable allylic and benzylic radicals react smoothly with 6. 

Scheme 5.5 Tributyltin hydride-mediated addition of tert-butyl iodide (8) to dimethyl 2-cyclohexyl-4-methylene glutarate (9), stereoselectively giving syn-dimethyl 2-cyclohexyl-4-neopentyl glutarate (10) via transient adduct radical 11 in the presence of Sc(OTf)3.

Figure 5.9 (a) ESI mass spectrum in the positive ion mode of the reacting solution of the tributyltin hydride-mediated addition (1.25 mmol of tert-butyl iodide (8)... 

---