51646-11-8Relevant academic research and scientific papers
Radical chain reduction of alkylboron compounds with catechols
Villa, Giorgio,Povie, Guillaume,Renaud, Philippe
supporting information; experimental part, p. 5913 - 5920 (2011/06/16)
The conversion of alkylboranes to the corresponding alkanes is classically per-formed via protonolysis of alkylboranes. This simple reaction requires the use of severe reaction conditions, that is, treatment with a carboxylic acid at high temperature (>150 °C). We report here a mild radical procedure for the transformation of organoboranes to alkanes. 4-tert-Butylcatechol, a well-established radical inhibitor and antioxidant, is acting as a source of hydrogen atoms. An efficient chain reaction is observed due to the exceptional reactivity of phenoxyl radicals toward alkylboranes. The reaction has been applied to a wide range of organoboron derivatives such as B- alkylcatecholboranes, trialkylboranes, pinacolboronates, and alkylboronic acids. Furthermore, the so far elusive rate constants for the hydrogen transfer between secondary alkyl radical and catechol derivatives have been experimentally determined. Interestingly, they are less than 1 order of magnitude slower than that of tin hydride at 80 °C, making catechols particularly attractive for a wide range of transformations involving C-C bond formation.
The Use of a Phosphine Containing a Basic Group in the Mitsunobu Esterification Reaction
Camp, David,Jenkins, Ian D.
, p. 1835 - 1839 (2007/10/02)
Use of diphenyl(2-pyridyl)phosphine instead of triphenylphosphine in the Mitsunobu esterification reaction facilitates isolation of the desired ester.The resulting phosphine oxide is readily removed by a dilute acid wash. 31P n.m.r. investigations of the
Formation of Iodides and Esters from Alcohols and Tributyldiiodophosphorane and Diiodotriphenylphosphorane
Haynes, Richard K.,Holden, Malcolm
, p. 517 - 524 (2007/10/02)
Tributyldiiodophosphorane and diiodotriphenylphosphorane, prepared in situ from the corresponding phosphine and iodine, are generally able to convert primary and secondary alcohols into iodides at room temperature in diethyl ether or benzene containing two equivalents of hexamethylphosphoric triamide.Tertiary alcohols, as gauged by the lack of the reactivity of t-butyl alcohol, are, however, inert to this iodinating agents. 6-Hydroxyhexanoic acid yields a mixture of 6-iodohexanoic acid and 7-heptanolide.The first reagent also promotes facile condensation of secondaryand tertiary alcohols with carboxylic acids to form hindered esters in good yields.The phosphorane derived from tris(dimethylamino)phosphine and iodine, while less effective as an iodinating agent, rapidly converts 6-hydroxyhexanoic acid into 6-iodo-N,N-dimethylhexanamide, and hexanoic and benzoic acids into the corresponding N,N-dimethylamides in excellent yields at room temperature.Treatment of 3β-tosylocholest-5-ene with lithium iodide yields 3β-iodocholest-5-ene, and not 3α-iodocholest-5-ene, as previously reported.
