Abstract
Transition metal catalyzed cycloisomerization, carboalkoxylations and rearrangement reactions of appropriately functionalized organic molecules are described in this dissertation. The thesis is divided in to three sections and total four parts for better understanding. Chapter I The first chapter is divided into two parts, the first part consist of gold catalyzed carboalkoxylations of 5-alkoxypent-1-yn-3-ol derivatives I-1a in DCM as a solvent to produce 2,6-dioxabicyclo[3.1.0]hexanes I-2a The second part describes two distinct Pt-catalyzed carboalkoxylations of alkynes. The cycloisomerization of 5-alkoxypent-1-yn-3-ol derivatives I-3 produces 2,6-dioxabicyclo[3.1.0]hexanes I-4; the mechanism is postulated to involve a hydroxyl-triggered [3.3]-sigmatropic allyl rearrangement. As the same catalysis is extensible to their tertiary alcohol analogues I-5a, distinct dihydrofuranyl alcohols I-6a were obtained through a [3.3]-allyl rearrangement that is not assisted by the hydroxyl group. Chapter II The second chapter deals with a gold catalyzed ring closure metathesis of 1-(2-(1-(allyloxy)hept-2-yn-1-yl)phenyl)ethanone derivatives II-1a in the methylene chloride as the reaction solvent to form 1-(1-methyl-1-(vinyloxy)-1H-inden-2-yl)pentan-1-ones II-2a. We postulate that this reaction is the formation of oxygen cyclobutene intermediate product through the open-loop process. Chapter III The last chapter discusses a gold-catalyzed isomerization of unactivated allenes into 1,3-dienes with nitrosobenzene as an additive. This reaction proceeded almost exclusively at room temperature for highly substituted allenes. The utility of this reaction is manifested by the development of one-pot [4+2]-cycloaddition of allenes and reactive alkenes.