Synlett 2009(13): 2203-2204  
DOI: 10.1055/s-0029-1217623
© Georg Thieme Verlag Stuttgart ˙ New York

DABAL-Me3: A Versatile Methylating Agent

Abhishek Goswami*
Natural Products Chemistry Division, North-East Institute of Science & Technology, Jorhat-785 006, Assam, India
Further Information

Publication History

Publication Date:
23 July 2009 (online)


DABAL-Me3 is a very suitable, easy to use reagent to ­methylate a variety of functional groups like aldehydes, imines, enones, amides, etc. Although trimethyl aluminium has been traditionally used as a methylating agent, its pyrophoric nature stands as a major obstacle in its sustainability. Several other Me3Al˙NR3 species such as Me3Al˙pyridine, Me3Al˙TMEDA (tetramethyletyhylenediamine) are also reported, but they are too reactive to be used under normal laboratory conditions. DABAL-Me3, which is actually a 2:1 complex of Me3Al and DABCO, is free from these shortcomings as it can be manipulated without the need for an inert atmosphere. [¹] [²]

DABAL-Me3 can be prepared by adding neat AlMe3 to freshly sublimed DABCO in toluene at 0 ˚C. The white precipitate is separated from toluene and washed several times with diethyl ether. [³] The versatility of the reagent can be easily assessed by its capability to methylate a wide variety of substrates.


  • 1 Bradford AM. Bradley DC. Hursthouse MB. Motevalli M. Organometallics 1992.  11 p., 111 
  • 2 Woodward S. Synlett  2007,  1490 
  • 3 Biswas K. Prieto O. Goldsmith PJ. Woodward S. Angew. Chem. Int. Ed.  2005,  44:  2232 
  • 4 Cooper T. Novak A. Humphreys LD. Walker MD. Woodward S. Adv. Synth. Catal.  2006,  348:  686 
  • 5 Alexakis A. Albrow V. Bisaws K. d’Augustin M. Prieto O. Woodward S. Chem. Commun.  2005,  2843 
  • 6 Novak A. Humphreys LD. Walker MD. Woodward S. Tetrahedron Lett.  2006,  47:  5767 
  • 7 Glynn D. Bernier D. Woodward S. Tetrahedron Lett.  2008,  49:  5687