Reduction reaction with organolithium compounds

Alkenyl trityl ketones, prepared by reaction of 1 with a ketone followed by dehydration, undergo exclusive conjugate addition on reaction with organolithium compounds. The adducts are cleaved to primary alcohols on reduction with LiB(C2H5)3H. 

The approach to thiopyrans involving reductive alkylation and arylation consists of the reaction of organolithium compounds or Grignard reagents with the corresponding thiopyrylium salts. 

The N-N bond of polystyrene-bound hydrazines, which are prepared by reaction of organolithium compounds with resin-bound hydrazones [457], can be cleaved by treatment with borane to yield a-branched, primary amines (Entry 9, Table 3.23). An additional example of reductive cleavage to yield amines is shown in Entry 10 (Table 3.23), in which a resin-bound a,a-disubstituted nitroacetic ester undergoes decarboxylation and reduction to the primary amine upon treatment with lithium aluminum hydride. 

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