3-Methyl-2-Butenal

Introduction

3-Methyl-2-butenal, also known as 3,3-dimethylacrolein, is a very interesting reagent used in addition and cyclo­addition reactions. This colorless, light-yellowish liquid has a pungent odor and is miscible in common organic solvents and water. It is commercially available, but it can also be prepared by oxidation of 3-methyl-2-butenol with H₂O₂. Kon et al. have reported this reaction with a yield of 91%. [¹]

3-Methyl-2-butenal is an α,β-unsaturated carbonyl compound. This compound has interesting properties that result from the conjugation of the carbon-carbon double bond with the carbonyl group and the two electrophilic sites: The carbonyl carbon and the carbon atom that is in β-position to it. The polarization of electron density makes their β-carbon atoms rather electrophilic. [²]

Various examples of the use of 3-methyl-2-butenal are found in the literature. This reagent has been explored for the preparation of 1,4-dihydropiridines, [³] diene adducts, [4] pyranonaphthoquinones, [5] nitropentanal pyrrole, [6] cyclization precursors, [7] and 2H-chromenes. [9]

References

• 1 Kon Y. Usui Y. Sato K. Chem. Commun.  2007,  4399 
• 2 Carey FA. Organic Chemistry   McGraw-Hill; New York: . 
• 3 Moreau J. Duboc A. Hubert C. Hurvois J. Renaud J. Tetrahedron Lett.  2007,  48:  8647 
• 4 Hong B. Wu M. Tseng H. Liao J. Org. Lett.  2006,  8:  2217 
• 5 Kumar S. Malachowski WP. Hadaway JB. Londe JM. Carroll PJ. Jaller D. Metz R. Prendergast GC. Muller AJ. J. Med. Chem.  2008,  51:  1706 
• 6 Kim H. Dogutan DK. Ptaszek M. Lindsey JS. Tetrahedron  2007,  63:  37 
• 7 Clark AJ. Geden JV. Thom S. Wilson P. J. Org. Chem.  2007,  72:  5923 
• 8 Ko S. Lin C. Tu Z. Wang Y. Wang C. Yao C. Tetrahedron Lett.  2006,  47:  487 
• 9 Chauder BA. Lopes CC. Lopes RSC. da Silva AJM. Snieckus V. Synthesis  1998,  279