Aromatic Helical Foldamers as Nucleophilic Catalysts for the Regioselective Acetylation of Octyl β‐d‐Glucopyranoside,ChemPlusChem

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Aromatic Helical Foldamers as Nucleophilic Catalysts for the Regioselective Acetylation of Octyl β‐d‐Glucopyranoside
ChemPlusChem ( IF 3.0 ) Pub Date : 2020-11-04 , DOI: 10.1002/cplu.202000685
Geunmoo Song ₁ , Kyu‐Sung Jeong ₁

Affiliation

Two indolocarbazole‐naphthyridine foldamers 2 and 3 that fold into helical conformations were prepared. The 4‐(N,N‐dimethylamino)pyridine (DMAP) moiety was introduced at one end of the foldamer strands to develop foldamer‐based catalysts for the site‐selective acylation of polyols. These foldamers adopt helical conformations containing internal cavities capable of binding octyl β‐d‐glucopyranoside. The association constants were determined to be 1.9 (±0.1)×10⁵ M⁻¹ for 2 and 2.1 (±0.1)×10⁵ M⁻¹ for 3 in CH₂Cl₂ at 25 °C. In the presence of DMAP, 2 or 3 as the catalysts, octyl β‐d‐glucopyranoside was subjected to acetylation under identical reaction conditions. The DMAP‐catalysed reaction afforded the random distribution of the monoacetylates (6‐OAc : 4‐OAc : 3‐OAc : 2‐OAc=33 : 24 : 41 : 2). In contrast, foldamers 2 and 3 led to the predominant formation of 6‐OAc. The relative distributions were estimated to be 6‐OAc : 4‐OAc : 3‐OAc=88 : 4 : 6 : ∼0 with 2 and 6‐OAc : 4‐OAc : 3‐OAc : 2‐OAc=90 : 3 : 6 : 1 with 3.

中文翻译：

芳香族螺旋Foldamers作为辛基β-d-葡萄糖苷的区域选择性乙酰化的亲核催化剂

准备了两个折叠成螺旋构象的吲哚并咔唑-萘啶折叠剂2和3。将4-（N，N-二甲基氨基）吡啶（DMAP）部分引入折叠链的一端，以开发用于多元醇的位点选择性酰化的基于折叠的催化剂。这些折叠剂采用螺旋构型，其中包含能够结合辛基β - d-吡喃葡萄糖苷的内腔。的缔合常数被确定为1.9（±0.1）×10 ⁵ 中号^-1为2和2.1（±0.1）×10 ⁵ 中号^-1为3在CH ₂氯₂在25°C下。在DMAP的存在下，以2或3作为催化剂，在相同的反应条件下对辛基β - d-吡喃葡萄糖苷进行乙酰化。DMAP催化的反应提供了单乙酰化物的随机分布（6-OAc：4-OAc：3-OAc：2-OAc = 33：24：41：2）。相反，折叠剂2和3导致6-OAc的主要形成。相对分布估计为6-OAc：4-OAc：3-OAc = 88：4：6：-0与2和6-OAc：4-OAc：3-OAc：2-OAc = 90：3： 6：1与3。

更新日期：2020-11-18

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