Carboxylic boryl esters

Other boryl esters of dithiocarboxylic acids 69 are obtained by sulfurization of the corresponding carboxylic acids, esters or amides with organoboron sulfides such as (9-BBN)2S andbis(l,5-cyclooctanediylboryl) sulfide (Scheme 16) [124,125]. Methanolysis of the boryl esters 69 gives the corresponding dithiocarboxylic acids. 

Scheme 16 Formation of boryl esters of dithiocarboxylic acids by sulfurization of the corresponding carboxylic acids, esters or amides with an organoboron sulfide...

Recent optimization studies reveal that the yield of 2-(2-propenyl)-1,3,2-dioxaborolane-4,5-di-carboxylate esters (i.e., the tartrate ester modified allylboronates) is improved by using triiso-propyl borate as the borylating agent1. The improved yields are directly related to the increased efficiency of the preparation of the intermediate allylboronic acid. 

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