Competition of Methanol and <i>Tert</i>-Butanol in Nucleophilic Substitution at Phosphorus Atom
作者:Agnieszka Cieplucha、Stefan Jankowski
DOI:10.1080/10426500902947690
日期:2009.6.23
2,3-Oxaphosphabicyclo[2.2.2]octene 1 reacts with alcohols simultaneously according to two competitive mechanisms: bimolecular addition-elimination and unimolecular elimination-addition with the intermediacy of metaphosphonate Ph-PO 2 ( 2 ). In 1,2-dichloroethane at 60°C, cyclic phosphinate 1 reacts with methanol in the bimolecular reaction five times faster than with tert-butanol. The reaction of metaphosphonate
The O-insertion reaction of a 7-phos- phanorbornene (3) unsubstituted on the double- bond gave the corresponding 2,3-oxaphosphabicyclo- [2.2.2]octene oxide (4a) in a regioselective manner that was useful in the fragmentation-related phosphonylation of alcohols. Both the UV-light mediated and the thermoinduced phosponylation accomplished on the bridged P-heterocycle (4a) were found to be sensitive toward