Reactions of N-Methylated Amino Acids and Benzylammonium Ions with P73- and As73-: Unusual Stereospecific Alkyl Group Transfers in the Synthesis of R2P7- and R2As7- Ions

摘要: Ethylenediamine (en) solutions of E73-, where E = P (1) or As (2), react with excess (PhCH2)Me3NBr to give NMe3 and a single diastereomer the (PhCH2)2E7- ions, (3) (4), in good yields. X-ray crystal structures [PPh4]3 [K(2,2,2-crypt)]4 salts showed that both anions adopt sterically favored symmetrical structure. DMF 1 also ethyl esters N-methylated amino acids, (EtOCOCHR)Me3N+, R H (glycine) Me (alanine), (EtOCOCHR)2P7- ions (7) (8). The transfer Me+ known Me2P7- ion (5) is competitive (EtOCOCHR)+ when not proton such 5 over formation 8 (5:8 2.5:1), but only trace impurity for (5:7 ≈ 1:48). Reactions S enantiomers alanine were conducted probe stereochemistry at carbon these reactions, three different diastereomers (i.e., (R,R)- (S,S)-, (R,S)-, (S,R)-(EtOCOCHR)2P7-) indistinguis...