TiCl4-promoted addition of nucleophiles to open chain α-amidoalkylphenyl sulfones

Efficient Synthesis of N-Carbamoylpropargylamines from α-Amido Sulfones Using Dimethylalkynylaluminum Reagents

Dimethylalkynylaluminum reagents derived from terminal alkynes and trimethylaluminum underwent addition to various N-activated α-amido sulfones to produce the corresponding alkynylamines in moderate to excellent yields. The optimized protocol avoids the preparation and isolation of relatively unstable N-activated imines that are generated in situ from their corresponding, stable, N-activated α-amido sulfones. This methodology provides access to a wide range of alkynylamines containing N-carbamoyl, -acyl, and -sulfonyl moieties.

Bismuth-catalyzed addition of silyl nucleophiles to carbonyl compounds and imines

Bismuth triflate was found to be an efficient catalyst both in the Mannich-type reaction of silyl enolates and in the Sakurai reaction of allyltrimethylsilane with N-alkoxycarbonylamino sulfones. The reactions proceeded smoothly with a low catalyst loading of Bi(OTf)(3)·4H(2)O (0.5-5.0 mol%) to afford the corresponding protected β-amino carbonyl compounds and homoallylic amines in very good yields (up to 96%). The latter compounds could also be obtained via a bismuth-mediated three-component reaction. We have also developed an efficient vinylogous Mukaiyama aldol reaction of 2-(trimethylsilyloxy)furan with various aromatic aldehydes mediated by bismuth triflate in a low catalyst loading (1 mol%). The reaction proceeds rapidly and affords the corresponding 5-[hydroxy(aryl)methyl]furan-2(5H)-ones in high yields with good to very good diastereoselectivities (diastereoisomeric ratios>98:2). Such selectivities, although previously reported with other Lewis acids, could be achieved with a much lower catalyst loading. 5-[Hydroxy(alkyl)methyl]furan-2(5H)-ones derived from ketones could also be obtained with good diastereoselectivities. The vinylogous Mukaiyama aldol reaction has also been extended to 2,2-dimethyl-6-methylene-4-(trimethyl-silyloxy)-1,3-diox-4-ene using 1 mol% of Bi(OTf)(3)·4H(2)O.

Solventless Clay-Promoted Friedel−Crafts Reaction of Indoles with α-Amido Sulfones: Unexpected Synthesis of 3-(1-Arylsulfonylalkyl) Indoles

Friedel-Crafts reaction of indoles with alpha-amido sulfones in the presence of montmorillonite K-10 leads unexpectedly to 3-(1-arylsulfonylalkyl) indoles in good yield. The obtained products can be further desulfonylated under reductive or alkylative conditions giving linear and branched 3-substituted indoles.

The first catalytic Sakurai reaction of N-alkoxycarbonylamino sulfones with allyltrimethylsilane

We report the first catalytic Sakurai reaction of N-alkoxycarbonylamino sulfones with allylsilanes. The allylation reaction of N-alkoxycarbonylamino phenylsulfones with allyltrimethylsilane proceeded smoothly with low catalyst loading of bismuth triflate (2.0 mol%) to afford the corresponding protected homoallylic amines in moderate to very good yields (up to 96%).