Palladium-Catalyzed Markovnikov-Selective Hydroselenation of N-Vinyl Lactams with Selenols Affording N,Se-Acetals
摘要:
The highly regioselective hydroselenation of N-vinyl lactams has been revealed to successfully afford the corresponding N,Se-acetals as Markovnikov adducts. In the case of terminal N-vinyl lactams, Markovnikov-selective hydroselenation proceeds efficiently in the absence of any catalyst (or additive), owing to the acidity of the selenols. In contrast, the self-promoted hydroselenation is inefficient with internal N-vinyl lactams. In the presence of palladium diacetate (Pd(OAc)(2)), however, the desired hydroselenation of internal N-vinyl lactams proceeds efficiently to afford the corresponding N,Se-acetals.
Rhenium-Catalyzed Hydroamidation of Unactivated Terminal Alkynes: Synthesis of (E)-Enamides
摘要:
Reactions of cyclic amides with unactivated terminal alkynes in the presence of a catalytic amount of a rhenium complex provided (E)enamides in high regio- and stereoselectivity (E:Z = > 99:< 1).
Synthesis of sterically hindered enamides via a Ti-mediated condensation of amides with aldehydes and ketones
作者:Julien Genovino、Bharat Lagu、Yaping Wang、B. Barry Touré
DOI:10.1039/c2cc32538a
日期:——
The first TiCl(4)-mediated condensation of secondary amides with aldehydes and ketones has been achieved. The reaction proceeds at room temperature and is complete within 5 h in most cases. The optimized procedure used 5 equiv of an amine base hinting that the in situ activation of both the amide and the Lewis acid is required. The reaction affords polysubstituted (E)-enamides.
Regioselective Hydrothiolation of Alkenes Bearing Heteroatoms with Thiols Catalyzed by Palladium Diacetate
作者:Taichi Tamai、Akiya Ogawa
DOI:10.1021/jo500586a
日期:2014.6.6
examples of transition-metal-catalyzed hydrothiolation of alkynes, the corresponding catalytic addition of thiols to alkenes has remained undeveloped. However, a novel Pd-catalyzed addition of thiols to alkenes bearing a heteroatom, such as oxygen and nitrogen, is found to proceed under mild conditions to give the corresponding Markovnikov adducts, regioselectively, in good yields.