Divergent reactivity of divinylsilanes toward sulfonamides in different oxidative systems

Abstract

The products of NBS-induced halosulfonamidation of divinylsilanes undergo base-induced cyclization providing new heterocycles including the hitherto unknown 1,3,5-diazasilinanes in up to quantitative yield.

Triflamidation of Allyl-Containing Substances:Unusual Dehydrobromination vs. Intramolecular Heterocyclization

“…By replacing acetonitrile with THF as a solvent, we hoped to synthesize amino esters, as was previously successfully completed in our works [ 18 , 19 ]. However, with allyl chloride, instead, the product of bromination, 1,2-dibromo-3-chloropropane 16 , was isolated in a low yield ( Scheme 10 ) indicating that triflamide is not involved in the reaction.…”

“…Amidines similar to 14 containing bromine at the β-position to the amidine nitrogen atom readily undergo base-induced intramolecular cyclization to afford 5-substituted 2-methyl-1-triflyl-4,5-dihydro-1 H -imidazolines in up to quantitative yield [ 16 , 19 , 20 , 21 ]. With this in mind, we examined the reaction of amidine 14 with potassium carbonate and triethylamine in acetonitrile and found that dehydrobromination did occur but, instead of the expected 5-cyanomethylimidazoline 24 , N-[3-cyanoprop-2-en-1-yl)]-N’- (triflyl)ethaneimidamide 25 was unexpectedly formed.…”

“…Earlier, the products of oxidative sulfonamidation with THF interception have been shown to undergo base-induced intramolecular heterocyclization to the corresponding 1,4-oxazocanes [ 19 ]. However, as in Scheme 15 , the reaction of compound 17 with potassium carbonate, instead of cyclization, occurred as dehydrobromination to the isomeric linear products, N -(4-((3-cyanoallyl)oxy)butyl)triflamide 27 and N -(4-((3-cyanoprop-1-en-1-yl)oxy)butyl)triflamide 28 in the ratio of 1:2 ( Scheme 15 ) and the total yield of 80%.…”

Halosulfonamidation of camphene: chemo and stereoselectivity, rearrangement, solvent interception, heterocyclization

“…We found only a few examples, including a hydroamination reaction of camphene with mesylamide 16 and the preparation and functionalization of a sultam derivative of camphene as a catalyst in asymmetric synthesis. [17][18][19][20][21] With this in mind, and given our continued interest in oxidative sulfonamidation, [22][23][24][25][26][27]…”

“…With this in mind, and given our continued interest in oxidative sulfonamidation, 22–27 in this work we investigated the reactions of oxidative addition of sulfonamides RSO 2 NH 2 1a–k (R = CF 3 ) ( a ), 4-MeOC 6 H 4 ( b ), 4-MeC 6 H 4 ( c ), Ph ( d ), 4-ClC 6 H 4 ( e ), 4-BrC 6 H 4 ( f ), 4-NO 2 C 6 H 4 ( g ), 2-CF 3 C 6 H 4 ( h ), 4-CF 3 C 6 H 4 ( i ), NH 2 ( j ), Me ( k ) to camphene 2 in the presence of NBS, NIS, and t BuOCl/NaI in the solvents MeCN and CH 2 Cl 2 .…”