The Mukaiyama reagent (2-chloro-1-methylpyridinium iodide, CMPI) is one of the most valuable reagents for ­activation of hydroxyl groups of carboxylic acids and ­alcohols.[¹] It is a pale yellow crystalline solid which is stable at room temperature in closed containers under normal storage and handling conditions. CMPI is commercially available, but can be easily synthesized from 2-chloro­pyridine and methyliodide.[2a] [b] [c] [d]

It is widely used for the synthesis of esters,[³] lactones,[⁴] ­amides,[⁵] lactams,[⁶] and ketenes[⁷] from the corresponding carboxylic acids, as well for obtaining carbodiimides from thioureas[⁸] and thiocyanates from alcohols.[⁹] CMPI was introduced as an useful reagent for the synthesis of carboxylic esters by Teruaki Mukaiyama in 1975,[¹⁰] after that the miscellaneous N-alkyl-2-halopyridinium salts had been developed as activating agents.[¹] Nowadays, several polymer-supported CMPI analogues have been used for the synthesis of esters and amides due to user-friendly purification procedures.[¹¹] The reagent analogues are also valuable for peptide synthesis.[¹²]

Mukaiyama试剂（2-氯-1-甲基吡啶碘化物，CMPI）是活化羧酸和醇的羟基最有价值的试剂之一。[ ¹ ]它是淡黄色结晶固体，在室温下稳定。在正常的储存和处理条件下密闭的容器。CMPI是可商购的，但可以很容易地由2-氯吡啶和甲基碘合成。[2a] [b] [c] [d]

它广泛用于由相应的羧酸合成酯，[ ³ ]内酯，[ ⁴ ]酰胺，[ ⁵ ]内酰胺，[ ⁶ ]和乙烯酮[ ⁷ ]，以及从硫脲[ ⁸ ]和从醇硫氰酸盐。[ ⁹ ] CMPI被引入作为用于通过向山辉明羧酸酯在1975年合成中的有用的试剂，[ ¹⁰ ]，该杂项后ñ烷基-2-卤代吡啶鎓盐已经开发作为活化剂。[ ¹如今，由于用户友好的纯化程序，几种聚合物支持的CMPI类似物已用于酯和酰胺的合成。[ ¹¹ ]试剂类似物对于肽的合成也很有价值。[ ¹² ]