Source: https://www.sigmaaldrich.com/china-mainland/zh/chemistry/chemical-synthesis/learning-center/chemfiles/chemfile-2001-2003/vol-3-no-1/monomeric-phosphazene-bases.html
Timestamp: 2019-04-24 00:43:19+00:00

Document:
We offer four monomeric phosphazene bases P1, i.e. 79412, 20025, 79408 and 79432, which differ with respect to their steric hindrance and basicity (Table 1).
All four P1 bases mentioned in Table 1 are distillable liquids and can be easily handled with syringe techniques. Regarding many favorable features they resemble DBU. However, in comparison to DBU (MeCNpKBH+ = 24.3) they are less nucleophilic, far less sensitive towards hydrolysis and 2-4 orders of magnitude more basic. Furthermore, they are particularly suitable for deprotonation (activation) of pronucleophiles. The P1 bases have become important tools e.g. in the field of nucleic acid chemistry,[2,3,4,5] amino acid or peptide synthesis,[7-11] and solid-phase chemistry.[12,13] See Table 2 for a list of our P1 bases with their properties, package size etc.
Especially interesting for solution phase synthesis and high-throughput chemistry is Merrifield-resin-bound BEMP 20026 (2-tert-Butylimino-2-diethylamino-1,3-dimethyl-perhydro-1,3,2-diazaphosphorine). This base combines the ease of use, separation and recovery of a supported reagent with the outstanding features of BEMP as a base. It is used successfully as a strong and anhydrous base for synthesis with polymeric reagents[17-25] in parallel synthesis.
Applications: The P1 phosphazene bases have a broad application area in organic synthesis. They can be used for alkylation-,[2-6,8-11,13-15,18-27] michael-addition-,[7,12,16,28,29] ester saponification-, acylation-,[30,31] silylations, aldol-condensation- and heterocumulene reactions, as well as in reactions involving transition metals.[35,36] Occasionally, the P1 bases are suitable for E2-eliminations. Among the successfully converted substrates are alcohols,[2,3,25] phenols, thiols,[26,34,35] NH-acidic heterocycles,[2,4,5,14,18,23,24,25] amines,[20,22,30] hydrazones, hydrazids, amides, sulfonamides, malonic esters, benzophenone imines of glycine esters,[6,7,8,13] imides, acetoacetic ester, a-phenylsulfinyl esters, cyano- and isocyanoacetic esters.[11,28,29] Acrylic esters, N-arylamides, dihydrobenzofuranes, pyrroles, pyrazoles, 3-thio-1,2,4-triazoles, isoindoles, glycosides[2,26] nucleoside analogues,[4,5,24] and epibatidine have thus been efficiently synthesized.
Schwesinger, R. et al., Chem. Ber. 1994, 127, 2435.
Schwesinger, R., Chimia 1985, 39, 269.
Kachalova, A. V. et al., Nucleos. Nucleot. Nucl. 2000, 19, 1693.
Knapp, S., Gore, V. K., Organic Lett. 2000, 2, 1391.
Lukin, K. A. et al., Nucleos. Nucleot. Nucl. 2000, 19, 815.
O4Donnell, M. J. et al., Tetrahedron Lett. 1998, 39, 8775.
O4Donnell, M. J. et al., Tetrahedron Asymm. 2001, 12, 82.
Scott, W. L., O4Donnell, M. J. et al., J. Org. Chem. 2002, 67, 2960.
Guillena, G., Najera, C., Tetrahedron Asymm. 1998, 3935.
Najera, C. et al., Synthesis 1999, 704.
Kotha, S. et al., Bioorg. & Med. Chem. Lett. 2002, 12, 1113.
Paulitz, C., Steglich, W., J. Org. Chem. 1997, 62, 8474.
O4Donnell, M. J., Aldrichim. Acta 2001, 34, 3.
Heinelt, U. et al., Bioorg. & Med. Chem. Lett. 2001, 11, 227.
Du, X., Armstrong, R. W., J. Org. Chem. 1997, 62, 5678.
Jung, G. et al., J. Org. Chem. 1999, 64, 1362.
Garcma-Ochoa, S. et al., Tetrahedron Lett. 2001, 42, 6675.
Xu, W. et al., Bioorg. & Med. Chem. Lett. 1998, 8, 1089.
Ley, S. V. et al., Bioorg.& Med. Chem. Lett. 1999, 9, 2049.
Ley, S. V. et al., J. Chem. Soc., Perkin Trans. 1 1999, 1253.
Ley, S. V. et al., Bioorg. & Med. Chem. Lett. 2000, 10, 1983.
Ley, S. V., Massi, A., J. Chem. Soc., Perkin Trans. 1 2000, 3645.
Ley, S. V. et al.,J. Chem. Soc., Perkin Trans. 1 1999, 107.
Kim, K. et al., Tetrahedron Lett. 2000, 41, 3573.
Schwesinger, R., Nachr. Chem. Tech. Lab. 1990, 38, 1214.
Koh, J. T. et al. Carbohydr. Res. 2000, 325, 169.
T. Allmendinger, Tetrahedron 1991, 47, 4905.
Uno, H. et al., Synthesis 1999, 471.
Lash, T. D. et al., Synlett. 2000, 213; Lash, T. D., Gandhi, V., J. Org. Chem. 2000, 65, 8020.
Kim, K., Le, K., Synlett. 1999, 1957.
Prinzbach, H. et al., Chem. Ber. 1992, 125, 1719.
Prinzbach, H. et al., Angew. Chem. Int Ed. Engl. 1989, 28, 298 .
Montforts, F. P., Schwartz, U. M., Liebigs Ann. Chem. 1991, 709.
Graybill, T. L. et al., Tetrahedron Lett. 2002, 43, 5305-5309.
Jaun, B. et al., Chem. Eur. J. 2000, 6, 3508.
Buchwald, S. L. et al., J. Am. Chem. Soc. 2002, 124, 7421.

References: V. 
 V. 
 V. 
 V. 
 V. 
 V.