82902-64-5Relevant academic research and scientific papers
Regioselective Diboron-Mediated Semireduction of Terminal Allenes
Gates, Ashley M.,Santos, Webster L.
, p. 4619 - 4624 (2019/12/11)
A method for the regioselective reduction of the terminal double bond of 1,1-disubstituted allenes has been developed. In the presence of a palladium catalyst, tetrahydroxydiboron and stoichiometric water, allene semireduction proceeds in high yield to afford Z-alkenes selectively.
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.
Substituted o-benzyl p-Tolyl Sulfones: Practical Reagents for Preparing Cycloadducts of o-Quinodimethanes
Lenihan, Brian D.,Shechter, Harold
, p. 7505 - 7508 (2007/10/02)
Effective methods for synthesis and 1,4-elimination of silyl sulfones to o-quinodimethanes have been developed.
Photochemistry of (o-Methylphenyl)alkenes and the Stereospecific Trapping of the Resulting o-Xylylenes
Hornback, Joseph M.,Barrows, Russel D.
, p. 4285 - 4291 (2007/10/02)
The photochemical behavior of a series of o-methylstyrenes with simple alkyl groups in the α or β positions was investigated in order to determine the synthetic potential of the resulting o-xylylenes.The major photochemical product of all the styrenes employed (1,9,10, and 11) was the corresponding o-xylylene.The o-xylylenes were trapped in acceptable yields by maleic anhydride to give the Diels-Alder adducts.In the case of 9 or 10 and 11 the o-xylylynes were produced stereoselectively and trapped stereospecifically to give 15 or 16 respectively.In the absence ofa dienophile or in the presence of a weak dienophile, such as cyclohexene, a slower isomerization of the o-methylstyrenes to the meta isomers was observed, presumably via a benzvalene intermediate.In addition, the o-xylylene produced from 9 or 10 and 11 underwent geometrical isomerization in the absence of maleic anhydride, resulting in the formation of 10 and 11 upon irradiation of 9 and vice versa.
