The hydrophosphonation of saturated hydrocarbons

The photophosphonylation of cyclohexane has been successfully carried out using radiation from a mercury source. With dialkyl hydrogenphosphonates yields of dialkyl cyclohexylphosphonates reaching 75-80% were obtainable within one day, and the esters (EtO)RP(0)H produced similar, or at least acceptable, yields of mixed phosphinic esters CyRP(0)0Et (R = Et, Ph, or Cy) under similar conditions  

High reactivity is shown towards hydrogenphosphonates by highly strained hydrocarbon molecules. Thus, 1,3-dedihydroadamantane (133) reacts to give esters of 1-adamantyl-phosphonic acid under non-homolytic conditions , and tricyclo[4.1.0.0 ]heptane similarly affords the phosphonic esters 134 . 

Synthesis from Phosphorus(lll) Compounds and Carbonyl Compounds 

Reactions between simple carbonyl compounds and simple phosphorus(III) halides or esters have been studied periodically throughout more than a century of organophos-phorus chemistry and still surface periodically for further examination. This is perhaps not surprising in the light of uncertainties still surrounding the mechanisms of combination, and also the wide variety of products which have been obtained from simple starting materials. 

The behaviour of aldehydes and ketones towards dialkyl and trialkyl phosphites will be considered later in connection with the synthesis of (1-hydroxyalkyl)phosphonic acids and 

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