Insights into the Molecular Recognition Process in Organocatalytic Chemoselective Monoacylation of 1,5-Pentanediol
Insights into the Molecular Recognition Process in Organocatalytic Chemoselective Monoacylation of 1,5-Pentanediol
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DOI：
10.1002/adsc.201600010
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发表时间：
2016-04-14
影响因子：
5.4
通讯作者：
Kawabata, Takeo
中科院分区：
文献类型：
--
作者：
Imayoshi, Ayumi;Yamanaka, Masahiro;Kawabata, Takeo
长链线性二醇的单酰化经常遇到与不可避免的过酰化相关的困难，从而提供二酰化物。然而，几个C-1-和C-2-对称的吡咯烷吡啶（PPY）催化剂被发现有效地促进化学选择性的1，5-戊二醇的单酰化。考察了催化剂结构对单酰化反应性能的影响。在C-1和C-2对称催化剂中，吡咯烷环上的酰胺羰基在选择性单酰化反应中起关键作用。另一方面，吲哚NH基团的酰胺侧链的催化剂被发现是至关重要的，进一步提高单酰化的化学选择性，只有当催化剂具有C-2-对称结构。通过密度泛函理论计算，阐明了催化剂结构对化学选择性单酰化反应的影响，揭示了催化剂对1，5-戊二醇精确分子识别的机理和这些官能团对过渡态稳定作用的机理.
Monoacylation of long-chain linear diols often encounters difficulties associated with unavoidable overacylation affording the diacylate. However, several C-1- and C-2-symmetrical pyrrolidinopyridine (PPY) catalysts were found to effectively promote the chemoselective monoacylation of 1,5-pentanediol. The effects of catalyst structure on the performance for the monoacylation were investigated. The amide carbonyl group(s) in the pyrrolidine ring in both C-1- and C-2-symmetrical catalysts was(were) suggested to play the key role in selective monoacylation. On the other hand, the indolyl NH group in the amide side chain of the catalysts was found to be critically important for further increasing the chemoselectivity of monoacylation only when the catalyst has a C-2-symmetrical structure. The effects of the catalyst structure on the chemoselective monoacylation were elucidated by DFT calculations, and the origin of the precise molecular recognition for 1,5-pentanediol by the catalysts and transition state (TS) stabilization effects by these functionalities were disclosed.