General Papers ARKIVOC 2015 (vii) 354-361 Page 354 © ARKAT-USA, Inc A mild and convenient oxidative transformation of aldehydes to methyl esters using iodosobenzene in combination with KBr Loveena Arora a , Richa Prakash b* , Om Prakash c , and Nitya Sharma b a Department of Chemistry, National Institute of Technology, Kurukshetra, Haryana, India b Department of Chemistry, Kurukshetra University, Kurukshetra, Haryana, India c Madhav University, Abu road, Sirohi, Rajasthan, 307026, India E-mail: prakashricha@rediffmail.com DOI: http://dx.doi.org/10.3998/ark.5550190.p009.267 Abstract Oxidation of various aliphatic and aromatic aldehydes with iodosobenzene in combination with potassium bromide in aqueous methanol offers a mild and convenient method for their conversion into the corresponding methyl esters. The method is not straightforward for the synthesis of heteroaryl esters. Keywords: Organohypervalent iodine(III) reagents, iodosobenzene, oxidation, methyl esters Introduction Oxidative transformation of aldehydes (1) into esters (2) is a very useful reaction in organic synthesis. A number of methods using various reagents have been reported to bring about this transformation (Scheme 1). 1-9 However, many of these procedures suffer from several limitations such as involvement of toxic heavy metal oxidants, expensive catalyst, large excess of reagents, and dry solvent in inert atmosphere. Furthermore, the requirement of poisonous 3 and polluting reagents, mediators, and cocatalysts along with long reaction times and drastic reaction conditions causes severe economic and operational problems. Thus, alternative methods for this transformation are desirable. Organohypervalent iodine reagents 10-19 have been increasingly used in contemporary organic synthesis. In particular, organoiodine(III) reagents, namely (diacetoxyiodo)benzene, 20 bis(trifluoroacetoxy)iodobenzene, 21 [hydroxy(tosyloxy)iodobenzene] 22 and iodosobenzene (IOB) 23 have emerged as versatile oxidizing agents. Organoiodine(III) reagents in combination with other reagents have also shown interesting applications in organic synthesis. For example, Kita et al. 24,25 have reported that iodosobenzene in combination with KBr (system i) in aqueous methanol can be employed for the oxidative transformation of alcohols into methyl esters. This reaction has been suggested to proceed through the intermediacy of aldehyde, but these were not isolated. Based on these observations, it was considered worthwhile to examine the oxidation of