Gold-catalyzed cycloisomerizations of ene-ynamides
作者:Sylvain Couty、Christophe Meyer、Janine Cossy
DOI:10.1016/j.tet.2008.10.108
日期:2009.2
The gold-catalyzedcycloisomerizations of 1,6-ene-ynamides proceed under mild conditions and lead to cyclobutanones from terminal or trimethylsilyl substituted ynamides, or to carbonyl compounds bearing a 2,3-methanopyrrolidine subunit from substrates possessing a propargylic alcohol moiety. High diastereoselectivities are observed with 1,6-ene-ynamides having a stereocenter at the α or β position
We present the first productive ring-closing metathesis reaction that leads to the construction of cyclic alkenyl bromides. Efficient catalysis employing commercially available Grubbs II catalyst is possible through appropriate modification of the starting bromoalkene moiety.
Convenient Syntheses of Chiral Cyclic Sulfinates (Sultines) from Unsaturated Alcohols
作者:Charles M. Marson、Paul R. Giles
DOI:10.1021/jo00129a056
日期:1995.12
The reaction of unsaturated alcohols with N-sulfinyl-p-toluenesulfonamide (TsNSO) is shown to lead stereoselectively to chiral cyclic or bicyclic sulfinates (sultines). The reactions occur at ambient temperatures and afford a general route to delta- and epsilon-sultines which are notable for their crystallinity and thermal stability. These studies confirm the preservation of stereochemical integrity of the carbon atom alpha to the oxygen atom in the sultine ring. Some unsaturated aldehydes furnish sultines via a tandem oxo-ene cyclization and subsequent ring closure to the sultine. In some reactions, N-toluenesulfonamide derivatives of sultines (compounds of type 11) were isolated, and since those were converted into the sultines by the action of BF3-OEt(2), such sulfonamides are considered to be intermediates in the reaction pathway.