ISSN:
0075-4617
Keywords:
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Description / Table of Contents:
The cis/trans Ratio in Allylidene(triphenyl)phosphoranes Prepared from Dialkylaluminium Alkylidenamides and Methylene(triphenyl)phosphoraneDialkylaluminium alkylidenamides 1 react in ether with methylene(triphenyl)phosphorane to give the allylidene(triphenyl)phosphoranes 2 and dialkylaluminium amides 4; crystallisation from ether at -78°C enables 2 to be separated from 4. Using this method the compounds 2, mentioned in table 1 and eq. (1). have been prepared for the first time in pure form and characterised by their 1H-NMR spectra. It has been shown by 1H-NMR spectroscopy that the compounds 2a- i are formed in yields of 70-80%, as the cis-form 2A, while compounds 21 and m are formed in yields of more than 95%; as the trans-form 2B.
Notes:
Dialkylaluminium-alkylidenamide 1 reagieren nach Gleichung (1) mit Methylen(triphenyl)- phosphoran in Äther zu Allyliden(triphenyl)phosphoranen 2 und Dialkylaluminiumamiden 4; durch anschließende Kristallisation aus Äther bei -78°C lassen sich die Verbindungen 2 von dem gleichzeitig anfallenden 4 trennen. Nach dieser Methode wurden die in Tabelle 1 angegebenen Verbindungen 2 erstmals rein dargestellt und durch ihre 1H-NMR-Spektren (Tabelle 2) charakterisiert. Danach fallen die Verbindungen 2a-i zu 70-80% in der cis- Form 2A, die Verbindungen 2l und m zu über 95 % in der trans-Form 2B an.
Additional Material:
1 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jlac.197519750411
