Cubane amides lithiation

The regioselective syn, vicinal lithiation of cyclopropane and cubane amides has been reported. Transmetalation to organomercury or zinc compounds facilitates functionalization, as shown in Scheme 43. 

Eaton and co-workers also reported the synthesis of 1,3,5-trinitrocubane and 1,3,5,7-tetranitrocubane (39) ° The required tri- and tetra-substituted cubane precursors were initially prepared via stepwise substitution of the cubane core using amide functionality to permit ort/jo-lithiation of adjacent positions. The synthesis of precursors like cubane-1,3,5,7-tetracarboxylic acid was long and inefficient by this method and required the synthesis of toxic organomercury intermediates. Bashir-Hashemi reported an ingenious route to cubane-1,3,5,7-tetracarboxylic acid chloride (35) involving photochemical chlorocarbonylation of cubane carboxylic acid chloride (34) with a mercury lamp and excess oxalyl chloride. Under optimum conditions this reaction is reported to give a 70 8 22 isomeric mixture of 35 36 37... 

It has been shown that lithiation with lithium amides can also be regioselective (see 2-21).277 In the case of the cubane derivative 30, a saturated unactivated position was regio-selectively lithiated.278... 

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