Current Organic Chemistry - Volume 6, Issue 12, 2002

The choice of polymeric support plays a key role in the success of solid phase methods for the synthesis of organic compounds. In the past decades, numerous efforts have been dedicated to the development of new polymeric materials with improved swelling in water and organic solvents and increased stability under a wide range of reactions conditions for their use in solid phase organic synthesis. Herein, we present a review of these various types of resins and their applications.

Linear triquinanes, those tricyclopentanoid systems that feature three five-membered rings fused together in an extended fashion, constitute a particularly interesting class of sesquiterpenoid natural product. The uniqueness of their architecture, the challenge of adroitly introducing the pendant methyl groups, and the proper resolution of those special problems associated with the regiocontrolled introduction of oxygen functionality have attracted many practitioners of organic synthesis. The result has been the development of novel synthetic strategies and the resourceful application of new reactions.This review focuses on two target molecules, hypnophilin and ceratopicanol, and contrasts the several synthetic routes that have been reported for their de novo synthesis. Attention is directed in particular to the global efficiency of each approach.

This review deals with recent progress in the synthesis of fluorine-containing heterocyclic compounds using the fluorinated building block method. Several fundamental fluorinated building blocks such as fluorinecontaining multiple bond compounds, fluoroalkyl substituted carbonyl compounds are described in detail, they are readily prepared and easy to scale up from the commercial available starting materials such as RfX, RfCXYZ (X, Y, Z: halogen), (CF3CO)2O etc. Under mild reaction condition, they react with various organic reagents to give a variety fluoroalkyl substituted N, S, O-heterocycles.

Palladium catalysed reactions serve as versatile tools in synthetic organic chemistry. By using these methodologies carbon monoxide can be introduced directly into a number of different sites in an organic molecule leading to the synthesis of carbonyl compounds and carboxylic acid derivatives.The substrate is reacted with a nucleophile such as an alcohol (alkoxycarbonylation), a primary or secondary amine (aminocarbonylation) or water (hydroxycarbonylation) or an organometallic reagent (formylation, crosscoupling reactions) in the presence of carbon monoxide and a palladium complex. Cyclocarbonylation, leading to a variety of heterocyclic compounds, can be regarded as a special type of the former reactions. Double carbonylation usually takes place at elevated CO pressures and produces α-ketoamides or -esters. Cascade reactions may be defined as multireaction ‘one-pot’ sequences in which the first reaction creates the functionality to trigger the second one. The use of two-phase processes makes catalyst recovery and recirculation, one of the greatest drawbacks of homogeneous catalytic processes, possible. As palladium-catalysed carbonylations usually tolerate a great variety of functional groups, they are attractive methods for the selective synthesis of intermediates of natural or biologically active products.The reactions mentioned above can often be achieved in good yield and with high selectivity usually under very mild conditions. Because of the vast number of publications in this field, this review is dealing only with the conversion of organic halides and its contents is limited to the description of the most recent developments published until the end of 2001.