Organic reactions—continued sequential

The organic layer obtained from the phosphide reaction still under argon is rapidly transferred by cannula into the stirred-nickel(II) solution. A yellow-brown precipitate forms immediately. The aqueous layer from the phosphide reaction, still in the reaction flask under argon, is extracted with three successive 50-mL portions of diethyl ether added via syringe, and the diethyl ether extracts are transferred by cannula into the nickel(II) mixture. The stirring of the mixture is continued for about 5 min and then it is filtered through a 170-mL glass filter with 25- to 50-// porosity and washed sequentially with two 60-mL portions of 95% ethanol and three 60-mL portions of pentane. The air-stable yellow-brown precipitate is then sucked dry on the frit. 

A wide range of taxonomically distinct organisms is able to degrade or transform xenobiotics, and reactions carried out under anaerobic conditions merit continued attention. Sequential transformations reactions carried out by different organisms may be necessary to accomplish degradation of the initial substrate, and attempts to mimic such situations in laboratory experiments have been illuminating. 

As an extension of the Heck reaction, Pd-catalyzed hydroarylation of alkynes and alkenes continues to attract high level of research interest in simple coupling processes and in cyclization reactions. The use of this type of transformation as part of a domino reaction will be of increasing interest. The research in the field of domino reactions is attracting considerable attention in synthetic organic chemistry since it enables the rapid assembly of complex molecules in one-pot processes. Very elegant examples of palladium-catalyzed cascade processes where a single catalytic cycle entails several sequential bond transformations have been recently reported [la, b, 2a, b, c]. 

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