Phosphine catalyzed [3+2] cycloaddition reactions for the synthesis of carbo-and heterocycles

• Main Author: Magesh Sampath
• Other Authors: Loh Teck Peng
• Format: Theses and Dissertations
• Language: English
• Published: 2012
• Subjects: DRNTU::Science::Chemistry::Organic chemistry::Organic synthesis
• Online Access: https://hdl.handle.net/10356/48046
• Institution: Nanyang Technological University

This thesis describes the development of phosphine as nucleophilic catalyst in cycloaddition reactions and its application in the synthesis of structurally diverged carbo- and hetero cyclic frameworks. Chapter 1 In chapter 1, the phosphine catalyzed cycloaddition between electron deficient allene/alkyne with various coupling functionalities such as C=C, C=N and C=O in the synthesis of respective carbo- and heterocycles are briefly discussed. Recent advancement in the asymmetric version of this reaction and its application in total synthesis of various natural products were also discussed. Chapter 2 In chapter 2, the phosphine catalyzed [3+2] cycloaddition reaction between α-trimethylsilyl substituted aryl allenones and electron deficient olefins are described. This new method brings highly functionalized cyclopentenes with a wide substrate scope. The preliminary investigation on asymmetric versions of the reaction gave cyclopentene product with good enantioselectivity. Chapter 3 In chapter 3, highly functionalized cyclopentenes were synthesized using a phosphine-catalyzed one-pot isomerization and [3+2]-cycloaddition of 3-alkynoates with electron-deficient olefins. Furthermore, the commercially available chiral phosphine DIPAMP was found to promote an asymmetric version of this reaction and produced products in high optical purity. Chapter 4 In chapter 4, the phosphine catalyzed one-pot isomerization and [3+2]-cycloaddition of 3-alkynoates with activated imines was described in the synthesis of pyrrolidines. The method was shown to be applicable to the formal synthesis of the bioactive Securinega alkaloid (±)-allosecurinine. Chapter 5 In chapter 5, an efficient protocol to produce spiro furan-oxindolines via phosphine catalyzed [3+2] cycloaddition between carbonyl functionality of oxindolinones and allenoate is described.