Research On The Palladium-Catalyzed Intramolecular Heck Reaction Of Alkenyl Alcohols

Alkenols unit is a kind of highly chemically active group,which is widely used as a good intermediate wherein the alcohol is ultimately converted into the corresponding carbonyl products through a terminating organometallic transformation at a site distant from the initial bond-forming event.In recent years,enriching the reaction types of alkenyl alcohols to synthesize distal carbonyl compounds has become an important research area in modern organic synthetic chemistry.In this thesis,a series of studies have been carried out on the efficient synthesis of indolines,β-tetrahydrocarbaline,dihydronaphthalenes and indenes by palladium-catalyzed intramolecular Heck reaction of alkenyl alcohols.The main contents are as follows:The first chapter describes the study of palladium catalyzed intramolecular Heck arylation of 2-(hydroxyalkenyl)iodobenzene to construct unsaturated indole skeletons.The scope of this method was explored by changing the substitution on 2-(hydroxyalkenyl)iodobenzene.The linkers between ortho-iodobenzene and distal double bond have also been varied to construct dihydrobenzofurans,indanes,tetrahydro-quinolines and naphthalenes,along with generate a romote carbonyl group.which are useful intermediates for the synthesis of natural products or drug molecules containing indoline unit.The second chapter describes the successful construction of various polycyclic indole skeletons by the palladium-catalyzed electrophilic cyclization/redox-relay Heck arylation reaction of 2-(hydroxyalkenynyl)sulfonanilides.With the optimized conditions in hand,the scope of this palladium(Ⅱ)-catalyzed cascade reaction was explored.This method successfully combines the electrophilic cyclization and redox-relay process("chain walking"),which constructs a tertiary stereocenter,two rings and three chemical bonds,and a carbonyl group far away from the tertiary stereocenters.The carbonyl group can undergo further derivatization(reduction,Wittig,condensation and reductive amination reaction)to produce variousβ-tetrahydrocarbaline derivatives.The proposed mechanism shown that the reaction underwent electrophilic cyclization,intramolecular redox-relay Heck.In the chapter third,a series of dihydronaphthalenes and indenes have been successfully constructed from o-iodophenyl alkenyl alcohols and alkynes by palladium-catalyzed intermolecular alkyne insertion/intramolecular Heck reaction.The optimized reaction conditions were obtained through the screening of a series of reaction conditions.Under the optimal reaction conditions,the substrates scope of o-iodophenyl alkenyl alcohols and alkynes were explored and a series of polysubstituted dihydronaphthalenes and indenes could be synthesized with good yields.the products of dihydronaphthalene skeleton were diversified through reduction and Wittig reactions.Based on the experimental observation,it was suggested that the reaction underwent oxidative addition,intermolecular alkyne insertion,intramolecular Heck,β-H elimination.This method effective combines the alkyne insertion and redox-relay process with good regio-and chemo-selectivity.