Acylsilanes and C-stannylimines as anion equivalents

Abstract

Su~?z+nni/y Acylsilanes and C-stannyliinines react with organic halides in the presence of KI~-18-crown-6 ether to give ketones and ketimines, respectively.

Highly Stereoselective Synthesis of Substituted γ‐Lactams from Acylsilanes

“…For example, the use of aldehydes as the second electrophile affords the β,γ‐dihydroxy amides in good yields. By employing this distinctive characteristic of acylsilanes,24–33 an intriguing possibility is the addition of an imine with an appropriate activating electron‐withdrawing group to access highly substituted γ‐amino‐β‐hydroxy amides. Importantly, the cyclization to the corresponding γ‐lactam might be accomplished directly if the activating group on the nitrogen atom is easily removed.…”

Access to carbon–carbon bonds

“…Organotins which are oc-and ß-heterosubstituted can also react with aryl halides 441 " 443 but, as already stated, the reactivity of ß-heterosubstituted organotins will be discussed in Part Four. Acyltin derivatives can be used for the acylation of organic halides with palladium catalysis 444 and similar acylations are possible using Cstannylimines with activation by fluoride ions 445 . Similarly, tributylstannylmethanol gives smooth hydroxymethylation of bromobenzene (60% yield).…”

“…However, with transition metal catalysis, methoxymethyltin derivatives can also give cross-coupling products 454 (Scheme 10.84 When the a-heteroatom is doubly bonded to the carbon atom a similar situation arises. C-Phenyl C-stannyl imines react directly with acyl chlorides to afford a-diketones in moderate yield 445 , while acyltriorganotins necessitate palladium complex catalysis but offer a versatile route to unsymmetrical a-diketones 477 (Scheme 10.85 When symmetrical a-diketones are desired, the reaction of hexaalkylditins under similar experimental conditions appears to be a convenient route 477 ' 478 . However, to avoid decarbonylation, the reactions are better performed under carbon monoxide.…”

Fluorid-induzierte fragmentierung von acetyldimethylphenylsilan

“…Aroyltrimethylsilane [1,2] und Heteroaroyltrimethylsilane [3} unterliegen in wasserhaitigern Tetrahydrofuran (THF) bei Raumtemperatur einer Fluorid-induzierten Si-C-Spaltung der Si-Acyl-Einheit. Mit dem Ziel, durch eine analoge Reaktion den Acetyl-Rest von Acetyldimethylphenylsilan (2) (erhältlich aus Chlordimethylphenylsilan gernäss Schema 1) abzuspalten, haben wir 2 in THF mit Tetra-n-butylammoniumfluorid-trihydrat (TBAF · 3H 2 0) umgesetzt.…”