Tri-n-butyltin hydride reacts with acid chloride, RCOCl, spontaneously at ambient temperatures to form n-Bu 3SnCl, RCHO, RC(O)OCH 2R, and a number of minor products. The reaction is not a radical chain process, nor are radicals involved as intermediates. The initial products are n-Bu 3SnCl and RCHO; it is not known whether these are formed in a direct reaction between n-Bu 3SnH and RCOCl or via an unstable chloroalkoxytin species, n-Bu 3SnOCHClR. The remaining products are formed by subsequent reactions of the aldehyde. Thus, the alkoxytin species, n-Bu 3SnOCH 2R, is formed from aldehyde and tin hydride. This can react further with RCOCl to form the ester RC(O)OCH 2R, with RCHO to form n-Bu 3SnOCH(R)OCH 2R, and with n-Bu 3SnH to form RCH 2OH. The aldehyde can also react with RCOCl to form the α′-chloro ester, RC(O)OCHClR.