Methoxymethylsilylene: (1 + 6)‐ and (1 + 4)‐cycloadditions to heterotrienes

Abstract

Co-pyrolytic gas phase reactions of I,2-dimethyl-

N-Heterocyclic Carbene Analogues with Low-Valent Group 13 and Group 14 Elements: Syntheses, Structures, and Reactivities of a New Generation of Multitalented Ligands

“…The first reported examples were the benzannulated species 297a-c of which only 297c could be characterized by X-ray analysis, while in the following years, other species have also been characterized (297d-f) (Figure 31). 164,285,286 Later, the unsaturated and saturated versions, 298 and 299, with diverse substitutents have also been reported. 77,[287][288][289] In addition to these typical structural motifs there are several novel backbones for NHGe.…”

“…The two most common techniques are first by deprotonation of the diamine followed by addition of SnCl 2 or second by direct addition of Sn[N(TMS) 2 ] 2 , which acts as both a base and a tin(II) source, to the ene-diamine (this technique has only been used for unsaturated and benzo-fused systems). The three typical categories of saturated (334), 363 unsaturated (335), 172,364 and benzo-fused (336) 164,286,[365][366][367][368] are known, and all reported examples are found in Figure 38. The largest variety of substituents can be found in the benzo-fused class including a large variety of bis(stanylenes) 337 with different linkers.…”

The Thermally Stable Silylene Si[{N(CH2But)}2C6H4-1,2]: Reactivity toward CO Double Bonds

“…Addition of a transient silylene or SiCp* 2 (Cp* = C 5 Me 5 ) to a CO double-bonded system is now well-known. Such reactions have involved ketones and aldehydes, − 1-oxadienes, , benzil, , 1-oxatrienes, or α-ketimines. , With the exception of SiCp* 2 [a stable Si(II) compound, behaving as a silylene], the silylenes in these reactions were generated in situ either by thermolysis or photolysis.…”

Silylenes

“…As mentioned in Section II.A, a series of thermally generated silylenes Me žž SiCl, Me žž SiOMe and Me žž SiNMe 2 has been reacted with butadiene, isoprene and 2,3-dimethylbutadiene to yield mixtures of silacyclopent-2-and 3-enes 19 . Competition experiments indicated that the heterodienes (and heterotriene) shown in equation 72 react more rapidly than the simple dienes studied, and the structures of the heterocyclic products suggested that initial attack of the silylene was on the heteroatom or the hetero olefinic bond 21,169 .…”