66950-75-2Relevant articles and documents
Betylates. 2. The formation and high reactivity of alkylbetylates
King, James Frederick,Lee, Teresa Mee-Ling
, p. 362 - 372 (2007/10/02)
Unhindered primary alkyl N,N-dimethylsulfamates (1) react with methyl fluorosulfate to give the corresponding alkyl fluorosulfates (3) and the betaine, Me3N(1+)SO3(1-) (4), evidently by way of the intermediate alkylbetylate fluorosulfate (2); with certain other alkyl esters (1) products of substitution, elimination, and rearrangement are formed.The reaction not only provides a potentially useful route to simple alkyl fluorosulfates, but serves to demonstrate the powerful nucleofugality of the betylate group.To obtain a method for predicting the reactivity of betylates, we have compared substituent parameters with rate constants in four series of nucleophilic displacement involving esters of the general structure ROSO2Z; correlation (of log k) with ?* is mediocre but a new parameter, ?15* with a "15percent resonance" contribution as defined by Swain and Lupton, gives good to excellent agreement in the four reaction series.Evidence is presented for formation of the 7-norbornyl cation via the betylate from 7-norbornyl N,N-dimethylsulfamate and methyl fluorosulfate.Comparison with what is known of the reactivities of 7-norbornyl p-toluenesulfonate and trifluoromethanesulfonate esters serves to confirm that betylates are among the most nucleofugal functions of which a derivative has been fully characterized.
