Applications of planar-chiral heterocycles in enantioselective catalysis: Cu(I)/bisazaferrocene-catalyzed asymmetric ring expansion of oxetanes to tetrahydrofurans
摘要:
A planar-chiral. C-2-symmetric bisazaferrocene ligand is shown to control the stereochemistry of Cu(I)-catalyzed ring expansions of oxetanes to tetrahydrofurans (C) 2001 Elsevier Science Ltd, All rights reserved.
A new approach for the synthesis of 9-membered N,N,O-heterocycles by Pd-catalyzed [6+3] dipolarcycloaddition of N-iminoisoquinolinium ylides and 2-vinyl oxetanes has been developed. The scope of this cycloaddition was demonstrated with 28 examples. This is another important synthetic strategy for medium-sized rings by employing N-iminoisoquinolinium ylides as ternary synthons.
<scp>Palladium‐Catalyzed</scp> [4+2] and [6+2] Dipolar Cycloadditions for the Construction of Benzo[<i>d</i>]isothiazole 1,<scp>1‐Dioxide</scp> Fused 1,<scp>3‐Oxazinanes</scp> and 1,<scp>3‐Oxazocanes</scp><sup>†</sup>
The Pd-catalyzed dipolar cycloaddition represents a significant synthetic strategy for the construction of useful heterocyclic compounds. This study developed the dipolar [4+2] and [6+2] cycloaddition reactions of benzo[d]isothiazole 1,1-dioxides (BDs) leading to the synthesis of BD-fused 1,3-oxazinane and 1,3-oxazocane derivatives, respectively. In particular, the synthesis of BD-fused 1,3-oxazinanes
Pd 催化的偶极环加成代表了构建有用杂环化合物的重要合成策略。本研究开发了苯并[ d ]异噻唑1,1-二氧化物(BD)的偶极[4+2]和[6+2]环加成反应,从而合成了BD稠合的1,3-恶嗪烷和1,3-分别是恶唑烷衍生物。特别是,BD-稠合 1,3-恶嗪烷的合成表现出区域选择性和对映选择性特征,从而产生具有良好产率、对映选择性和区域选择性(如果适用)的产品。此外,本工作中开发的[6+2]环加成反应代表了基于BDs合成中等大小环化合物的第一个策略。