ORGANOBORANES FOR SYNTHESIS. 12. THE REACTION OF ORGANOBORANES WITH NITROGEN TRICHLORIDE. A CONVENIENT PROCEDURE FOR THE CONVERSION OF ALKENES INTO ALKYL CHLORIDES VIA HYDROBORATION

Article abstract of DOI:10.1016/S0040-4020(88)90014-2

Trialkylboranes are readily converted to the corresponding alkyl chlorides by a free radical reaction with nitrogen trichloride (NCl3).Compared to many other chlorinating agents examined, NCl3 is a superior reagent for the effective conversion of organoboranes into alkyl chlorides.Combined with the high regioselectivity inherent in the hydroboration reaction, the treatment with NCl3 allows alkenes to be transformed into pure alkyl chlorides of predictable structure.This process constitutes valuable method for the anti-Markovnikov hydrochlorination of alkenes in 66-94percent yield.Experimental evidence indicates that this reaction proceeds via free radical intermediates.The reaction of organoboranes with NCl3 is comparable to or better than other methods, such as those requiring refluxing aqueous cupric or ferric chloride, or those producing hydrogen chloride as a by-product.Consequently, this procedure could be very useful for the conversion of acid-sensitive (e.g., certain bicyclic) alkenes into alkyl chlorides where extensive skeletal rearrangements occur in hydrogen chloride additions.