Phosphine catalyzed [3+2] cycloaddition reactions for the synthesis of carbo-and heterocycles
Date of Issue2011
School of Physical and Mathematical Sciences
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.
DRNTU::Science::Chemistry::Organic chemistry::Organic synthesis