Nucleophilic addition of phosphines to rhenium allenylidenes. Unprecedented double P–H bond activation to give an η1-P-phospha-1-butadienyl ligand†
Abstract
C
CPh2)]OTf (1) yielding γ-phosphonioalkynyl complexes [(triphos)(CO)2Re{C
CCPh2(PMe3−xPhx)}]OTf [x
= 0, (2); 1, (4); 2 (7)] which convert into the α-phosphonioallenyl derivatives [(triphos)(CO)2Re{C(PMe3−xPhx)
C
CPh2}]OTf [x
= 0, (3); 1, (5); 2 (6)] at higher tempereature. The reactions of 1 with secondary, PHPh2, and primary, PH2CH2Fc (Fc = ferrocenyl),
CCPh2(PHPh2)}]OTf (9) and the α-phosphonioallenyl [(triphos)(CO)2Re{C(PHPh2)
C
CPh2}]OTf (10) have been intercepted by insitu
PPh2)CH
CPh2}]OTf (8). With the
PHFc)CH
CPh2}]OTf (11) transforms into the η1-P-phospha-1-butadienyl complex [(triphos)(CO)2Re{P(CH2Fc)
CHCH
CPh2}]OTf (12) upon heating at 50 °C.