Straightforward synthesis of α,β-epoxysilanes from terminal epoxides by lithium 2,2,6,6-tetramethylpiperidide-mediated deprotonation-in situ silylation

Enamines from Terminal Epoxides and Hindered Lithium Amides

“…During our studies on the synthesis of trans-R, -epoxysilanes from terminal epoxides using LTMP and TMSCl in situ, 6 we repeated the reaction of 1,2-epoxyoctadecane with LTMP (2.5 equiv, THF, 25°C, 16 h) described by Yamamoto. 5 In agreement with the latter work, we obtained octadecanal in 77% yield (lit.…”

Three‐Membered Heterocycles. Structure and Reactivity

“…Hodgson and coworkers [670] have reported on a convenient method of deprotonating terminal oxiranes with lithium 2,2,6,6-tetramethylpiperidide (LTMP), followed by trapping of the anion with silyl-based electrophiles, to provide a,b-epoxysilanes in good yield. For example, chloro-epoxide 640 underwent clean conversion into epoxysilane 641 at 0 C. This approach improves upon an earlier method, which employed sparteine derivatives at very low temperature (À90 C) [671].…”

Metalated Epoxides and Aziridines in Synthesis

“…This can be used for the asymmetric synthesis of epoxides, such as that of (-)-disparlure from enantiopure sulfoxide 222 ( Use of LTMP as base [52] in situ with Me 3 SiCl allows straightforward access to a variety of synthetically useful a,b-epoxysilanes 232 at near ambient temperature directly from (enantiopure) terminal epoxides 231 (Scheme 5.55) [81]. Hence, overall, a stereoselective protodesulfinylation is achieved.…”

“…In direct contrast with the chemistry of epoxides [81], trapping of the intermediate lithiated aziridine was possible with external electrophiles (which would otherwise be incompatible in situ with LTMP). A range of trans-a,b-disubstituted aziridines were thus synthesized (Table 5.6).…”