Synlett 2007(8): 1328-1329  
DOI: 10.1055/s-2007-980339
SPOTLIGHT
© Georg Thieme Verlag Stuttgart · New York

T3P: A Convenient and Useful Reagent in Organic Synthesis

Ariel L. Llanes García*
Universidade Estadual de Campinas, Instituto de Química, ­UNICAMP, C.P. 6154, CEP 13083-970, Campinas, São Paulo, ­Brasil
e-Mail: ariel@iqm.unicam.br; e-Mail: ariel@cristalia.com.br;
Further Information

Publication History

Publication Date:
08 May 2007 (online)

Introduction

T3P is a highly reactive n-propyl phosphonic acid cyclic anhydride (II, Scheme 1) originally designed as a coupling agent. [1] T3P works both as coupling and as water removal reagent, offering several advantages over traditional reagents, such as high yields and purity, low toxicity, broad functional group tolerance, low epimerization tendency without any additives, and easy work-up (only water-soluble by-products, eliminating the need of chromatographic columns). [1] [2] It can be prepared from the reaction of propyl phosphonic acid (I, Scheme 1) with acetic anhydride at a temperature preferably in the range of 70-110 °C; then the oligomeric phosphonic acid anhydride intermediate is distilled at 0.01-50 mbar and a temperature range of 200-350 °C. The cyclic anhydride II is immediately dissolved in an inert organic solvent. [3] [4]

Scheme 1 Preparation of T3P

Although T3P has been mainly used as an effective and mild condensation reagent in peptide and peptidomimetic synthesis, [1-3] [5] new applications have recently been developed for this reagent, which include direct conversion of carboxylic acids into nitriles, [6] dehydrations of amides to nitriles, [6] formation of Weinreb amides, [7] β-lactam synthesis, [8] ester formations, [9] thiohydroxamic acid anhydride syntheses, [10] preparation of heterocycles, [11] alcohol ­oxidations, [12] and acylations. [13] The diverse advantages and applications of T3P show its potential as a reagent in or­ganic synthesis.

    References

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