Direct syntheses of 4-aryl-1,2,3,4-tetrahydroisoquinolines and 1-aryl-2,3,4,5-tetrahydro-3-benzoazepines via hydroamination of enol carbamates
作者:José Crecente-Campo、M. Pilar Vázquez-Tato、Julio A. Seijas
DOI:10.1016/j.tet.2009.01.098
日期:2009.3
An efficient and simple procedure for the syntheses of 4-aryl-1,2,3,4-tetrahydroisoquinolines and 1-aryl-2,3,4,5-tetrahydro-3-benzoazepines has been developed. The approach uses easily available starting materials and requires just three steps. The hydroamination of an enol carbamate is the key step. This general and direct method has been applied to the total synthesis of the natural alkaloid cherylline
Stereoselective Intermolecular Carbolithiation of Open-Chain and Cyclic 1-Aryl-1-alkenyl N,N-Diisopropylcarbamates Coupled with Electrophilic Substitution. Observation of p-Carboxylation in a Benzyllithium Derivative
作者:Jan Georg Peters、Michael Seppi、Roland Fröhlich、Birgit Wibbeling、Dieter Hoppe
DOI:10.1055/s-2002-20040
日期:——
1-Aryl-1-alkenyl N,N-diisopropylcarbamates (1) are obtained from alkyl aryl ketones and N,N-diisopropylcarbamoyl chloride (CbCl) by heating with excess pyridine. These undergo facile syn-carbolithiation by alkyllithium/diamine and produce configurationally stable lithiated benzyl carbamates, which have been trapped with different electrophiles. If the reaction is carried out in the presence of chiral
simple method for the synthesis of enol carbamates by irradiation with microwaves under solvent-free -conditions has been developed. The method has been applied to substituted acetophenones, cyclic aryl ketones and α-aryl ketones. Its main advantages are short reaction times, good conversions -except for nitro acetophenones, and the environmentally friendly nature of the process. For α-aryl ketones the
Treatment of alkenyl carbamates with sodium dispersion and a co-existing boron electrophile affords alkenylboronates via the reductive cleavage of the vinylic C–Obond. The key to this borylation is an instant trapping of reactive organosodium species with the co-existing boron electrophile.