Dinitrogen oxide was employed as a clean oxidant for various oxidations in the presence of a catalytic amount of dioxoruthenium tetramesitylporphyrin complex (Ru(tmo)(O) 2 ). A variety of olefins, secondary alcohols, and benzyl alcohols were smoothly oxidized to the corresponding epoxides, ketones, and aldehydes in high yields. In the oxidation of 9,10-dihydroanthracene derivatives, the competitive
3,5-Bis(trifluoromethyl)phenyl Sulfones in the Julia–Kocienski Olefination – Application to the Synthesis of Tri- and Tetrasubstituted Olefins
作者:Diego A. Alonso、Mónica Fuensanta、Carmen Nájera
DOI:10.1002/ejoc.200600478
日期:2006.10
with carbonylcompounds employing phosphazene base P4-tBu at room temp. in THF, affording tri- and tetrasubstituted olefins in good yields. The Julia–Kocienski olefination between primary alkyl BTFP sulfones 8a,b and aromatic and aliphatic ketones affords the corresponding trisubstituted alkenes in good yields and low stereoselectivities. On the other hand, higher yields and stereoselectivities are
demonstrated by the synthesis of an intermediate of a bioactive compound on a large scale. A facile and widely applicable method for the synthesis of N-substituted amidesfrom alkenes and amides using Brønsted acids was developed. Treatment of various alkenes with amides and an alkali metal halide or methanesulfonic acid in trifluoroacetic acid afforded the corresponding N-substituted amides in good to high
A metal‐free dehydrogenative Diels‐Alderreaction of substituted alkenes for the synthesis of tetrahydroisoindolinones has been exploited for the first time. This new method features functional group tolerance and broad substrate scope, providing an efficient access to biologically active tetrahydroisoindolinone skeletons with endo steroselectivity in good to excellent yields.
In the presence of a catalytic amount of dioxo(tetramesitylporphyrinato)ruthenium(VI) complex, nitrousoxide (N2O) oxidized trisubstituted olefins into the corresponding epoxides in good-to-high yields with high selectivities.