Origins of Stereoselectivity of Chiral Vicinal Diamine-Catalyzed Aldol Reactions
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- 作者：Adam SimonAlexander J. Yeh ; Yu-hong Lam ; K. N. Houk
- 刊名：Journal of Organic Chemistry
- 出版年：2016
- 出版时间：December 16, 2016
- 年：2016
- 卷：81
- 期：24
- 页码：12408-12415
- 全文大小：690K
- ISSN：1520-6904
文摘
The sources of asymmetric induction in aldol reactions catalyzed by cinchona alkaloid-derived amines, and chiral vicinal diamines in general, have been determined by density functional theory calculations. Four vicinal diamine-catalyzed aldol reactions were examined. The cyclic transition states of these reactions involve nine-membered hydrogen-bonded rings in distinct conformations. Using nomenclature from eight-membered cycloalkanes, the heavy atoms of the low-energy transition states are in crown (chair–chair) and chair-boat conformations. The factors that control which of these are favored have been identified.