Gold(I)-Catalyzed Synthesis of Optically Active 1,4-Oxazepan-7-ones
摘要:
Optically active seven-membered lactones, dimethyleneoxazepanones, were readily prepared in good yields from chiral beta-(N-propargylic)-amino-alpha-methylene carboxylic add tert-butyl esters in the presence of catalytic amounts of Ph3PAuCl and Cu(OTf)(2) A smooth 7-exo-dig cyclization was observed.
A radical cascade reaction of aza-1,6-enyne compounds using allyltributyltin
作者:Akio Kamimura、Koichiro Miyazaki、Takuji Kawamoto、Hidemitsu Uno
DOI:10.1016/j.tet.2016.04.078
日期:2016.12
The radical cascade reaction of allyltin with aza-1,6-enyne compounds was studied. Optically active aza-1,6-enynes underwent a radical cascade process in the presence of a high concentration of allyltributyltin to give stannolanes as the major isomer. Piperidines were also observed in small amounts when an allylic unit was introduced stereoselectively to the trans-position of the aryl group at the
Bicyclic dihydrothiophenes are readily prepared by a radical cascade cyclization reaction triggered by the addition of a thiyl radical under thermal or photoirradiation conditions. The translocated radical attacks the sulfur atom in the initial radical donor unit in an S(H)i manner. Sufficient stereoselectivity is achieved when a large excess of disulfide is used for the reaction under photoirradiation conditions. The reaction in the absence of solvents provides vinylsulfides instead of dihydrothiophenes. Thus, the sulfur atom in the thiyl radical serves as a sulfur biradical synthetic equivalent.