83845-46-9Relevant academic research and scientific papers
Synthesis and Conversions of Substituted o-[(Trimethylsilyl)methyl]benzyl p-Tolyl Sulfones to o-Quinodimethanes and Products Thereof
Lenihan, Brian D.,Shechter, Harold
, p. 2072 - 2085 (2007/10/03)
Use of o-[(trimethylsilyl)methyl]benzyl p-tolyl sulfone (3) for synthesis and cycloaddition of substituted o-quinodimethanes has been investigated. Sulfone 3 is prepared from 2-methylbenzyl alcohol (4) by reactions with n-BuLi and chlorotrimethylsilane to form o-[(trimethylsilyl)methyl]-benzyl alcohol (7) which phosphorus tribromide converts to o-[(trimethylsilyl)methyl]benzyl bromide (8). Displacement of 8 with sodium p-toluenesulfinate yields 3. Sulfone 3 is alkylated at its α-sulfonyl position upon deprotonation with n-BuLi followed by methyl iodide, ethyl, butyl, allyl, and benzyl bromides, and 5-bromo-1-pentene, respectively. Acylations occur using acid chlorides. Dialkylation occurs upon further reaction with n-BuLi and an alkyl halide. 1,4-Eliminations of α,α-dialkyl sulfones 11 with tetrabutylammonium fluoride (TBAF) give α,α-dialkyl-o-quinodimethanes (29); 3 is therefore a synthon for the o-quinodimethane-α,α-dianion (34). o-Quinodimethanes 29 undergo (1) cycloaddition with acrylonitrile, acrylate esters, and alkyl fumarates to yield 1,1-disubstituted-tetrahydronaphthalenes (30) and (2) 1,5-sigmatropic rear-rangements of hydrogen to give styrenes (32). The stereochemistries of the various cycloadditions reveal significant mechanism information.
Photochemistry of (o-Methylphenyl)alkadienes: Attempted Intramolecular Trapping of the Resulting o-Xylylenes
Hornback, Joseph M.,Barrows, Russell D.
, p. 90 - 98 (2007/10/02)
The photochemistry of a series of o-methylphenyl dienes was investigated in order to determine if the resulting o-xylylenes could be trapped in an intramolecular Diels Alder reaction in synthetically useful yields.Irradiation of 3 gave meta-isomer 4 as the major product along with lower yields of double bond migration product 5 and the desired cycloadduct 6.The best yield of 6 (24percent) was obtained by irradiation of 3 with a low-pressure mercury vapor lamp at low temperatures.The other compounds investigated gave none of the intramolecular Diels-Alder product of the o-xylylene.Irradiation of 17 gave only double bond migration product 18.Irradiation of 22 gave an excellent yield of (2+2) cycloadduct 23.Irradiation of 26 gave meta-isomer 28, double bond migration product 27, and 29, a (2+2) cycloadduct of 28.
