Burgess Dehydration
The Burgess reagent, also known as methyl N-(triethylammoniumsulfonyl)carbamate, is a mild and selective dehydrating reagent used in organic chemistry for the dehydration of secondary and tertiary alcohols to form alkenes. It was developed by Edward M. Burgess at Georgia Tech[3]. The reagent is particularly useful because it operates under mild conditions and is compatible with a variety of functional groups that might be sensitive to harsher conditions[3][4].
The mechanism of the Burgess dehydration typically involves the formation of a sulfamate ester intermediate from the alcohol, followed by an Ei (internal elimination) mechanism where β-hydrogen abstraction and elimination of the sulfamate ester occur through a six-membered cyclic transition state, leading to the formation of an alkene[5]. This reaction is irreversible due to the formation of very stable by-products, such as carbonyl sulfide and methanethiol[5].
The Burgess reagent is also used for the dehydration of primary amides to nitriles at room temperature, showcasing excellent chemoselectivity[2]. It is soluble in common organic solvents, and its use can lead to unexpected reactivity under certain conditions, such as microwave irradiation[6].
In summary, the Burgess reagent is a versatile tool in organic synthesis for the dehydration of alcohols and amides, providing a mild alternative to more traditional, harsher dehydration methods. It is particularly advantageous for substrates that are sensitive to rearrangement or other side reactions under strong acidic or basic conditions.
Citations:
[1] https://www.youtube.com/watch?v=f_qlGcfUpmk
[2] https://onlinelibrary.wiley.com/doi/pdf/10.1002/1521-3897(200006)342:5%3C518::AID-PRAC518%3E3.0.CO;2-7
[3] https://en.wikipedia.org/wiki/Burgess_reagent
[4] https://www.researchgate.net/publication/300158663_Burgess_dehydrating_reagent
[5] https://en.wikipedia.org/wiki/Ei_mechanism
[6] https://pure.au.dk/ws/files/197827930/Dehydration_reactions_in_polyfunctional_natural_products.pdf
[7] https://www.youtube.com/watch?v=t0IA7-EO-HI
[8] https://www.sciencedirect.com/science/article/pii/S0040403900866976
[9] https://www.sciencedirect.com/topics/chemistry/tertiary-alcohol
[10] https://www.ukessays.com/essays/chemistry/burgess-martin-dehydrating-reagents-2948.php
[11] https://www.thieme-connect.com/products/ejournals/pdf/10.1055/s-2000-6752.pdf
[12] https://www.scientificupdate.com/process-chemistry-articles/a-mild-method-for-dehydration-of-a-base-sensitive-primary-amide-toward-a-key-intermediate-in-the-synthesis-of-nirmatrelvir/
[13] https://pubchem.ncbi.nlm.nih.gov/compound/5748364
[14] https://www.guidechem.com/question/what-is-burgess-reagent-and-it-id124443.html
[15] https://www.thieme-connect.com/products/ejournals/pdf/10.1055/s-0028-1087527.pdf
[16] https://www.researchgate.net/publication/8244453_New_Uses_for_the_Burgess_Reagent_in_Chemical_Synthesis_Methods_for_the_Facile_and_Stereoselective_Formation_of_Sulfamidates_Glycosylamines_and_Sulfamides
[17] https://www.fishersci.com/shop/products/burgess-reagent-96/AAL2015503
[18] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6869970/
[19] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4605154/
[20] https://www.bhrunners.co.uk/training-area/hydration-electrolytes
[21] https://www.researchgate.net/publication/316457499_Regioselective_dehydration_of_a-hydroxymethyl_tetrahydrofurans_using_Burgess'_reagent_under_microwave_irradiation