ChemInform Abstract: Catalytic Staudinger/Aza‐Wittig Sequence by in situ Phosphane Oxide Reduction.

Abstract

Catalytic Staudinger/Aza-Wittig Sequence by in situ Phosphane Oxide Reduction.-A Staudinger/aza-Wittig process using catalytic amounts of 5-phenyldibenzophosphole is described. The process involves in situ reduction of the phosphine oxide to complete the catalytic cycle. The process is readily amenable for the synthesis of benzoxazoles, benzodiazepines, and a pyrrole. -(VAN KALKEREN, H. A.; TE GROTENHUIS, C.; HAASJES, F. S.; HOMMERSOM, C. A.; RUTJES, F. P. J. T.; VAN DELFT*, F. L.; Eur. J. Org. Chem. 2013, 31, 7059-7066, http://dx.doi.org/10.1002/ejoc.201300585 ; Inst. Mol. Mater., Radboud Univ. Nijmegen, NL-6525 AJ Nijmegen, Neth.; Eng.) -Mais 13-195

A novel and highly efficient esterification process using triphenylphosphine oxide with oxalyl chloride

“…Phosphonium, phosphinic salts and phosphine oxides as frequently used coupling reagents have been reported especially for some famous reactions such as the Wittig reaction [5][6][7][8][9][10], Appel reaction [11][12][13][14], Staudinger reaction [15][16][17][18][19][20] and Mitsunobu reaction [2,[21][22][23][24][25][26][27][28][29][30][31][32]. The Mitsunobu reaction, first reported by Mitsunobu et al in 1967 [21], converts an alcohol into a variety of other functional groups including esters, and this method could generate esters in excellent yield (90%) via the condensation of a carboxylic acid and alcohol with a mixture of triphenylphosphine (Ph 3 P) and diethyl azodicarboxylate (DEAD).…”

“…Mecinovic and co-workers reported an amide reaction mediated by the PPh 3 /CCl 4 system, and TPPO was reduced to PPh 3 via this reaction [41]. Consequently, these phosphorus oxides have been used for several catalytic reactions, such as the catalytic Wittig reaction [5][6][7][8][9][10], catalytic Appel reaction [11][12][13][14] and catalytic Staudinger reaction [15][16][17][18][19][20]. It is easy to find the operating cost so high that it is not suitable for industrial production.…”