Alkylidene triphenylphosphoranes

Alkylidene triphenylphosphoranes react with nitroso compounds to give imines [54]. 

Finally, alkoxycarbonyl groups can be introduced by treatment of alkylidene-triphenylphosphoranes with ethyl chloroformate ClCOOC2H5 461 in these cases the hydrogen chloride formed must be bound, as discussed above. 

Z)-Allylic selenides 179 are formed in 58—69% yield under Wittig conditions using salt-free alkylidene triphenylphosphorane. A-Chlorosuccinimide/carbamate-promoted [2,3]-sig-matropic rearrangement affords allylic amines 180 in 45—64% yield. The olefin is transformed to an acid by conversion to an aldehyde followed by Jones oxidation. The resulting D-amino acids 181 are produced in 58—72% yield with enantiomeric excess values of 78—84%. 

Setzt man Acyl-alkyliden-triphenylphosphorane d9 R 4= H mit 215 um, so isoliert man die Phosphoniumchloride 216, die beim Behandeln mit verdiinnter Na2C03-L6sung in der Kalte (0—25°C) in die Chlor-ketone 217 (50—90% Ausbeute) und Triphenylphosphinoxid uber-gehen 8),... 

Ketenimine 446 lagem Ylide 34 imter Bildung der stabilen N-Aiyl-a-imino-alkyliden-triphenylphosphorane 447 an... 

Die Ausbeuten an Ketonen steigen auf 70—99%, wenn man anstelle der Alkyliden-triphenylphosphorane 34 die entsprechende Alkyliden-tributylphosphorane, aus den entsprechenden Phosphoniumjodiden mit Li-organischen Verbindungen hergestellt, einsetzt. 

Alkyliden-triphenylphosphorane 46 und Nitrone 525 gehen eine Cycloaddition zu 1.2.5-PV-oxazaphospholidinen 526 ein i ). 

Oxydiert man Alkoxycarbonyl-alkyliden-triphenylphosphorane 102 mit I0dn04 oder NaJ04 so erhalt man ebenfalls a-Ketocarbon-saureester 575a. 

CF3)aHg and MegCd in glyme. The resulting complex, (CF3)2Cd-glyme is both air and moisture sensitive, and can transfer CFg to covalent metal halides, e.g., to SnXi. Alkylidene triphenylphosphorane complexes (18, M = Zn, Cd, or... 

Only two examples of an aromatic species of this isomer of fused pyridazine have been reported. The furo[3,2-f]-pyridazine, 276, has been prepared in modest yield from the pyridazine 275 upon treatment with carboalkoxymethyl-triphenylphosphoranes (Equation 98) <2004PS(179)97>. The structure was confirmed by spectroscopic evidence and results by rearrangement of an intermediate alkylidene structure. 

In addition to the above examples involving nitrogen (in Group V of the Periodic Table), a phosphorane analogue of a 1,3-thiazetidine 1,1-dioxide has been suggested as an intermediate in the reaction of alkylidene- and arylidene-triphenylphosphoranes with sulphenes derived from alkanesulphonyl fluorides. ... 

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