Other Advances in Methodology

1 Solution-Phase Combinatorial Synthesis Boger et al. [71] constructed mixtures containing iminodiacetic acid diamides functionalized diamide precursors were dimerized by means of reactions with bis(tributylstarmyl)acetylene using (PhjPl Pd as the catalyst and butylated hydroxytoluene (BHT) as an additive to give product libraries suitable for probing protein-protein interactions. 

2 Reactions Catalytic in Tin Maleczka and Terstiege [72] have published several papers in this area. They first developed a one-pot hydrostannylation/Stille couphng protocol for reactions between 1-alkynes and bromostyrene to give 1,3-dienes. A mixture of BUjSnCl (catalytic amount), polymethylhydrosiloxane (PMHS) and aqueous sodium carbonate (to convert the chloride to bis(tri-n-butyltin)oxide that reacts with PMHS to give BUjSnH in situ) in combination with Pd2(dba)j and trifurylphosphine leads to diene formation. Use of MejSnCl instead of the tributyltin chloride [73] improves yields drastically (to up to 90%). Further improvement is obtained in the third protocol reported [74a,b], which was used to prepare 

Microwave heating has also been used by this group to accelerate one-pot hydrostannylation/Stille coupling reactions [75], which are carried out in a sealed tube. 

Use of a zipper molecule with aryl iodide and double-bond functionaHties [77] leads to a significant increase in molecular complexity, the overall sequence resulting in the formation of five bonds, five stereocenters, two rings, and a tetrasubstituted carbon center. 

In a further development [78], the zipper molecule with an aryl iodide func-tionahty was bound to a Wang resin the Suzuki chemistry was also used, and three small libraries of 16 compounds were prepared. 

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Other advances in methodology fcr synthesis of deoxysugars include the reduction of triflatc esters with tetrabutylammonium borohydiide, and the same reagent was also used for reductive... 

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