Synthesis of a Donor‐Stabilized Silacyclopropan‐1‐one

Abstract

International audienc

A Base‐Stabilized Sila‐β‐Lactone and a Donor/Acceptor‐Stabilized Silanoic Acid

“…[7] The significantly short Si1-O1 distance (1.539 ) is comparable to those reported for base-stabilized silaureas (1.532-1.542 ) [5,7] and is much shorter than the endocyclic Si1-O2 single bond (1.691 ), thus suggesting a double bond character. [14] Moreover, the significantly larger Wiberg bond order for the silanone function (1.194) than that for the single Si1-O2 bond (0.446) also indicates its multiplebond character.…”

“…In the 29 Si NMR spectrum the signal corresponding to the silanone function appears as a doublet (d = À52.7 ppm, 2 J PSi = 11.2 Hz) at slightly lower field compared to 1 (d = À87.5 ppm), but in the range of base-stabilized silanones. [5,7] The two carbon atoms of the lactone ring were observed as two doublets at relatively low field (d = 80.1 ppm, 1 J CP = 85.8 Hz and d = 47.4 ppm, 2 J CP = 13.6 Hz). The 1 H NMR spectrum shows a doublet for the proton of the lactone ring with a large coupling constant (d = 4.51 ppm, 3 J PH = 20.4 Hz).…”

“…[4] M. Driess and co-workers also demonstrated that the stabilization of such species can be achieved by coordination of electron-donating ligands on the silicon center (type IV), which allowed the isolation of the first examples of a basesupported silaurea [5] and a silanoic silyl ester V. [6] We have also recently reported the synthesis of the first donorstabilized silacyclopropan-1-one of type IV. [7] Although these techniques allowed the synthesis of other silacarbonyl derivatives, such as silanoic acid anhydride VI [8] and pyridinium salts of silanoic acid VII, [9] only a few types of silacarbonyl compounds are available to date. [10] Here we present the synthesis of the first base-stabilized sila-b-lactone VIII and its unique reactivity with alcohols leading to the formation of a silanoic acid IX, more precisely, silicic acid monoethyl ester, which is a silicon analogue of monoethyl carbonate.…”

Silicium‐Sauerstoff‐Doppelbindungen: ein stabiles Silanon mit einem trigonal planar koordinierten Siliciumzentrum

“…einem vierfach koordinierten Siliciumzentrum und verzerrt tetraedrischer Geometrie isoliert, in denen das elektrophile Siliciumzentrum durch eine koordinierte Lewis-Base stabilisiert wird [15] und daher besser als zwitterionische Silanolate (Schema 1, B) beschrieben werden sollten. Das erste stabile Germanon (Eind) 2 Ge=O konnte ebenfalls kürzlich durch Ausnutzung der sterischen Stabilisierung durch die Eind-Substituenten (Eind = 1,1,3,3,5,5,7,7-Octaethyl-s-hydrindacen-4-yl) isoliert werden.…”

The quest for observation and isolation of oxyallyl derivatives

“…47 Interestingly the authors demonstrated that 47, which is a donor-stabilized silacyclopropanone, has a hybrid structure with a significant silaoxyallyl character (Scheme 21). Importantly, although carbon and silicon are both group 14 elements, they strongly differ in terms of electronegativity, atomic radii, capacity for hypervalence, etc.…”