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用HF方法在6-31G~*基组下,对手性含硫噁唑硼烷催化苯乙酮不对称还原反应进行了量子化学从头算研究.还原反应经历了催化剂-硼烷加合物、催化剂-硼烷-酮加合物、催化剂-烷氧基硼烷加合物的生成以及催化剂-烷氧基硼烷加合物的离解过程.催化剂-硼烷加合物、催化剂-硼烷-酮加合物和催化剂-烷氧基硼烷加合物的生成分别为放热、吸热、放热过程;催化剂-烷氧基硼烷加合物离解成催化剂和烷氧基硼烷为吸热过程.催化剂-硼烷-酮加合物和催化剂-烷氧基硼烷加合物都存在四种稳定的结构.最有利于氢转移的催化剂-硼烷-酮加合物结构是次低能量结构,并且具有扭曲的船形结构.催化剂-烷氧基硼烷加合物含有一个B—O—B—N四元环,尽管四元环有较大的张力,但加合物仍有较高的稳定性.
The ab initio study of the asymmetric reduction of acetophenone catalyzed by chiral sulfur-containing oxazaborolidines was carried out using the HF method in the 6-31G ~ * basis set. The reduction reaction underwent a series of experiments, including catalyst-borane adduct, catalyst - borane-ketone adduct, catalyst-alkoxy borane adduct formation, and the dissociation of the catalyst-alkoxyborane adduct Catalyst - borane adduct, catalyst - borane-ketone The formation of adduct and catalyst-alkoxy borane adduct respectively is exothermic, endothermic and exothermic; the dissociation of catalyst-alkoxy borane adduct into catalyst and alkoxyborane is endothermic Process.The catalyst-borane-ketone adduct and the catalyst-alkoxyborane adduct all have four stable structures.The catalyst-borane-ketone adduct structure most favored for hydrogen transfer is the second lowest energy Structure, and has a distorted boat-shaped structure.The catalyst-alkoxyborane adduct contains a B-O-B-N four-membered ring, and although the four-membered ring has a larger tension, the adduct is still higher Stability.