Cycloaddition and Oxidation Reactions of a Stable Thioaldehyde, (2,4,6-Tri-<i>t</i>-butyl)thiobenzaldehyde
作者:Soichiro Watanabe、Toshio Yamamoto、Takayuki Kawashima、Naoki Inamoto、Renji Okazaki
DOI:10.1246/bcsj.69.719
日期:1996.3
The title thioaldehyde 1 undergoes [4 + 2] cycloaddition with 2,3-dimethyl-1,3-butadiene at 160 °C and [3 + 2] cycloadditions with diphenylnitrilimine and mesitonitrile oxide at room temperature. The intermediary cycloadduct with mesitonitrile oxide undergoes cycloreversion to give 2,4,6-tri-t-butylbenzaldehyde and mesityl isothiocyanate as the final products. Oxidation of 1 with m-chloroperbenzoic acid (mCPBA) and dimethyldioxirane (9) gives a mixture of (E)- and (Z)-isomers of the corresponding S-oxides (sulfines), the former and the latter being kinetically and thermodynamically controlled products, respectively. Although both (E)- and (Z)-sulfines are not further oxidized by mCPBA, the (Z)-sulfine is oxidized with 9 to give 7-oxa-8-thia-2,4,6-tri-t-butylbicyclo[4.3.0]nona-2,4,9-triene 8,8-dioxide and 6,8-di-t-butyl-3,4-dihydro-4,4-dimethyl-1H-2-benzothiopyran 2,2-dioxide, both of which are intramolecular cyclization products of an intermediary thioaldehyde dioxide (sulfene).
标题硫代醛 1 在 160 °C 下与 2,3-二甲基-1,3-丁二烯发生[4 + 2]环加成反应,在室温下与二苯基硝基亚胺和氧化间腈发生[3 + 2]环加成反应。中间环加成产物与氧化间腈发生环化反应,最终产物为 2,4,6-三丁基苯甲醛和间苯三酚异硫氰酸酯。1 与间氯过苯甲酸(mCPBA)和二甲基二环氧乙烷(9)发生氧化反应,生成相应 S-氧化物(亚硫酸盐)的(E)-和(Z)-异构体混合物,前者和后者分别是动力学和热力学控制产物。虽然(E)-和(Z)-硫都不会被 mCPBA 进一步氧化,但(Z)-硫会被 9 氧化,生成 7-oxa-8-thia-2,4,6-tri-butylbicyclo[4.3.0]壬-2,4,9-三烯 8,8-二氧化物和 6,8-二叔丁基-3,4-二氢-4,4-二甲基-1H-2-苯并噻喃 2,2-二氧化物,这两种物质都是中间硫醛二氧化物(亚硫)的分子内环化产物。