Keigo Fugami

Synthesis of vinylcyclopentanes from vinylcyclopropanes and alkenes promoted by benzenethiyl radical

Abstract The reaction of dimethyl 2-vinylcyclopropane-1,1-dicarboxylate with butyl vinyl ether in the presence of a catalytic amount of PhSH provides dimethyl 3-butoxy-4-vinylcyclopentane-1,1-dicarboxylate in 82% yield.

Triethylborane-induced radical addition of alkyl iodides to acetylenes

Abstract Treatment of terminal acetylenes (R 1 Cue5fcCH) with secondary or tertiary alkyl iodides (R 2 I) in the presence of triethylborane provides the corresponding alkenyl iodides (R 1 C(I)ue5fbCHR 2 ) in good yields.

One-pot synthesis of tetrahydrofuran derivatives from allylic alcohols and vinyl ethers by means of palladium(II) acetate

Abstract Treatment of a mixture of allylic alcohol and vinyl ether in the presence of Pd(OAc) 2 provides 2-alkoxy-4-alkenyltetrahydrofuran in good yield.

Pd(O) promoted transformation of N-tosyl-2-(1,3-butadienyl)-aziridine into N-tosyl-2-vinyl-3-pyrroline

Abstract 1,3-Butadienylaziridines activated by N-tosyl group smoothly rearrange to vinylpyrrolidine derivatives in the presence of a catalytic amount of Pd(PPh 3 ) 4 . Transformation of dienylazetidines into vinylpiperidine derivatives is also described.

Triprenylstannyl radical or benzenethiyl radical promotedtransformation of 1,1-dialk oxycarronyl-2-(1,3-butadienyl)cyclopropanes into 2-ethenyl-3-cyclopentenes

Abstract Dimethyl 2-(1,3-butadienyl)cyclopropane-1,1-dicarboxylate reacts with catalytic amount of Ph3SnH in benzene at 80°C to provide dimethyl 2-ethenyl-3-cyclopentene-1,1-dicarboxylate in good yield. The transformation of N-tosyl-2-(1,3-butadienyl)aziridine into N-tosyl-2-vinyl-3-pyrroline is also described.

Organic synthesis with reagents derived from 3R3SiMgMe and MnCl2

Abstract Synthetically useful reactions mediated by reagents derived from 3 equiv. of R 3 SiMgMe and MnCl 2 are disclosed. (1) The manganese species reacted with terminal acetylenes to give 1,2-disilylated 1-alkenes. Mono- and bis(trimethylsilyl) acetylenes gave tri- and tetrasilylated ethenes, respectively, in good yields. Highly strained tetrakis(trimethylsilyl) ethene has now become easily accessible by this technique. (2) The reaction of alkenyl halides, alkenyl sulfides, and enol phosphates with the title reagents provides vinylsilanes in good yields. The method is also applicable to the synthesis of allylsilanes from allylic sulfides and ethers. (3) Treatment of 1,3-dienes with the manganese reagents provides silylated allylmanganese compounds which add to the carbonyl moiety with high regio-selectivity.

Transformation of n-tosyl-2-(1,3-butadienyl)aziridine into n-tosyl-2-ethenyl-3-pyrroline

Abstract 1,3-Butadienylaziridines or 1,3-butadienylazetidines activated by N-tosyl group smoothly rearrange to vinylpyrroline derivatives or vinylpiperidines in the presence of a catalytic amount of Pd(PPh 3 ) 4 . Triphenyltin radical induced rearrangement of title compounds is also described.

New syntheses of vinylsilanes and allylsilanes by cross-coupling of (R3Si)3MnMgMe with alkenyl and allylic compounds

Abstract The reaction of alkenyl halides, alkenyl sulfides, and enol phosphates with (R 3 Si) 3 MnMgMe provides vinylsilanes in good yields. The method is also applicable to the allylsilane synthesis from allylic sulfides and ethers.