Aminophosphonium salts, synthesis

Miscellaneous. The reaction of the aminophosphonium salt (156) with thiols and alkoxides affords a convenient, high-yield, single-step synthesis of unsymmetrical thioethers.141 The key intermediate is the alkoxyphosphonium salt (157), which undergoes nucleophilic attack by RS- at the alkoxy carbon. 

The synthesis of phosphazenes starting from aminophosphonium salts appears to be conveniently accomplished by the reaction of the phosphonium azide with sodamide in liquid ammonia solution 49... 

Bertrand et al. have introduced a stable acyclic a-aminophosphonium salt. Only basic phosphines, such as tris(dimethylamino)phosphine, allow for the synthesis of stable aminophosphonium salts. The species mentioned gave upon deprotonation with butyllithium the corresponding C-amino phosphorus ylide (Scheme 100/1). In contrast, two cyclic a-amino phosphonium salts were found to be stable despite the presence of weakly basic triarylphosphine moieties. The key intermediates were dicationic aldiminium salts that on treatment with sodium tert-butylate afforded the cyclic a-aminophosphonium salts under discussion (Scheme 100/2 and 3). In Scheme 100/2, the carbenoid intermediate involved is also shown. On treatment with LiHMDS or BuLi, the stable phosphonium salts were converted to the corresponding P-ylides (Scheme 100/2 and 3). In the second example, the cyclic ylide was transformed to a phosphinoarylenamine derivative via a carbenoid intermediate (Scheme 100/3). ... 

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