159884-69-2Relevant academic research and scientific papers
phosphonates: Synthesis from Allylic α- and γ-Hydroxyphosphonates and Application to Diastereoselective Formation of Substituted phosphonates
Oehler, Elisabeth,Kanzler, Silvia
, p. 867 - 876 (2007/10/02)
Various substituted (3-azido-1-alkenyl)phosphonates 3 (R3 = alkyl) or their equilibrium mixtures with the regioisomeric α-azidophosphonates 4 (R3 = Ph) have been synthesized from allylic α- or γ-hydroxyphosphonates 2 or 1 by Mitsunobu reaction with TPP/DEAD/HN3, and converted into the new phosphonates 6 upon heating in toluene with DBU catalysis.The transformation 3/4 --> 6 proceeds via base-catalyzed rearrangement to the (3-azido-2-alkenyl)phosphonates 5 and subsequent thermolysis.Reduction of the 2H-azirines 6 with NaBH4 in methanol at 5 deg C results in the predominant formation of the disubstituted aziridines cis-7.Addition of trimethylsilyl cyanide to compounds 6 yields stereoselectively the highly functionalized aziridines trans-8, while NaOCH3-catalyzed addition of dimethyl phosphite proceeds with even higher selectivity to yield the bisphosphonates trans-9 with excellent yields. - Key Words: Phosphonates / Azirines / Aziridinylmethylphosphonates / Azides, vinyl
