Zaidlewicz M, Kanth JV, Brown HC
H. C. Brown Center for Borane Research, Purdue University, West Lafayette, Indiana 47907, USA.
J Org Chem. 2000 Oct 6;65(20):6697-702. doi: 10.1021/jo0009090.
The following sulfides have been examined as borane carriers in comparison with dimethyl sulfide and 1,4-oxathiane: tert-butyl methyl sulfide, isoamyl methyl sulfide, ethyl isoamyl sulfide, tert-butyl isoamyl sulfide, diisoamyl sulfide, tetrahydrothiophene, tetrahydro-thiopyran, thioanisole, 3-ethylthiotetrahydrofuran, bis(3-tetrahydrofuryl) sulfide, and bis(2-methoxyethyl) sulfide. Their complexing ability toward borane increases in the following order: thioanisole < ether-sulfides < dialkyl sulfides < dimethyl sulfide. Borane adducts of the sulfides are liquids above 0 degrees C. The thioanisole adduct loses diborane at room temperature. The reactivity of the adducts toward 1-octene increases in the reversed order of the complexing ability of the sulfides. Diisoamyl sulfide has a mild, ethereal, agreeable aroma, its synthesis is economical and the borane adduct, 4.2 M in BH3, is stable over prolonged periods at room temperature. The sulfide can be recovered from hydroboration-oxidation products by distillation. Consequently, diisoamyl sulfide is a new promising borane carrier. Bis(2-methoxyethyl) sulfide, easily synthesized from the low cost thiodiethanol, is three times more soluble in water than 1,4-oxathiane. Its borane adduct is 6.0 M in BH3 and can substitute for more expensive borane-1,4-oxathiane in hydroboration reactions. Applications of these new borane adducts in the synthesis of mono- and dichloroborane adducts was also studied. The equilibrium ratios observed for the new chloroborane adducts were similar to that observed for dimethyl sulfide adducts. However, the hydroboration of 1-octene with these new chloroborane adducts are much faster than the corresponding adducts of dimethyl sulfide, which are currently used extensively.
已将以下硫化物作为硼烷载体进行了研究，并与二甲基硫醚和1,4 - 氧杂硫环戊烷作比较：叔丁基甲基硫醚、异戊基甲基硫醚、乙基异戊基硫醚、叔丁基异戊基硫醚、二异戊基硫醚、四氢噻吩、四氢硫代吡喃、苯甲硫醚、3 - 乙硫基四氢呋喃、双(3 - 四氢呋喃基)硫醚和双(2 - 甲氧基乙基)硫醚。它们对硼烷的络合能力按以下顺序增强：苯甲硫醚＜醚 - 硫化物＜二烷基硫醚＜二甲基硫醚。这些硫化物的硼烷加合物在0℃以上为液体。苯甲硫醚加合物在室温下会失去乙硼烷。加合物对1 - 辛烯的反应活性与硫化物的络合能力顺序相反。二异戊基硫醚具有温和、类似醚的宜人香气，其合成经济，且硼烷加合物（BH₃浓度为4.2 M）在室温下长时间稳定。该硫化物可通过蒸馏从硼氢化 - 氧化产物中回收。因此，二异戊基硫醚是一种新的有前景的硼烷载体。双(2 - 甲氧基乙基)硫醚可由低成本的硫代二乙醇轻松合成，其在水中的溶解度比1,4 - 氧杂硫环戊烷高三倍。其硼烷加合物的BH₃浓度为6.0 M，可在硼氢化反应中替代更昂贵的硼烷 - 1,4 - 氧杂硫环戊烷。还研究了这些新型硼烷加合物在单氯硼烷和二氯硼烷加合物合成中的应用。观察到的新型氯硼烷加合物的平衡比与二甲基硫醚加合物的相似。然而，用这些新型氯硼烷加合物对1 - 辛烯进行硼氢化反应比目前广泛使用的二甲基硫醚相应加合物快得多。
