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Phosphonium Ylides with Functionalized Silyl Substituents
Author(s) -
Dreihäupl KarlHeinz,
Angermaier Klaus,
Riede Jürgen,
Schmidbaur Hubert
Publication year - 1994
Publication title -
chemische berichte
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 0009-2940
DOI - 10.1002/cber.19941270908
Subject(s) - chemistry , phosphonium , heteronuclear molecule , ylide , substituent , silylation , crystallography , crystal structure , molecule , stereochemistry , medicinal chemistry , nuclear magnetic resonance spectroscopy , catalysis , polymer chemistry , organic chemistry
Two series of aminophosphonium ylides with reactive alkoxychlorosilyl substituents (R 2 N) 3 P=CHSi(OR') 2 Cl ( 1‐8 , R = Me, Et/R' = Me, Et, i Pr, t Bu) have been prepared by reaction of the aminophosphonium ylides (R 2 N) 3 P = CH 2 with the corresponding dialkoxydichlorosilanes Cl 2 Si(OR') 2 . Substituent effects have been investigated by heteronuclear solution NMR studies of the nuclei 1 H, 13 C, 15 N, 17 O, 29 Si, and 31 P. These studies show an alternating shielding effect along the C–O–Si–C backbone. Further reactions of the chlorosilylated ylides with the aminomethylenephosphorane (Me 2 N) 3 P=CH 2 lead to the formation of the bis‐ylidic compounds [(Me 2 N) 3 P=CH] 2 Si(OR') 2 ( 9 , 10 ), which are also available in one‐pot syntheses. The molecular structure of [(Me 2 N) 3 P=CH] 2 Si(O i Pr) 2 ( 9 ) has been confirmed by single‐crystal X‐ray diffraction. In the crystal the molecules have two ylidic carbon centers with planar configuration, which are bridged by a nearly tetrahedral silicon atom. Short P–C and Si–C distances indicate a stabilizing effect of the carbanionic centers.