نتایج جستجو برای: stable phosphorus ylides
تعداد نتایج: 300743 فیلتر نتایج به سال:
A DABCO-catalyzed (3 + 3) annulation between 2-(acetoxymethyl)buta-2,3-dienoate and sulfur ylides has been developed, which provides a facile method for the synthesis of 4H-pyrans bearing a vinyl sulfide group.
A highly trans-selective protocol for the synthesis of glycidic amides was developed. This approach gave access to oxiranes by reacting stabilised ammonium ylides bearing an α-carbonyl group and aromatic aldehydes in moderate to good yields.
A new type of chiral sulfur ylides has been synthesized and their reactivities against carbonyl compounds tested, showing a high degree of stereoselectivity in the formation of trans epoxy amides under very mild reaction conditions.
A phosphorus allotrope that has not been observed so far, ring-shaped phosphorus consisting of alternate P8 and P2 structural units, has been assembled inside multi-walled carbon nanotube nanoreactors with inner diameters of 5-8 nm by a chemical vapor transport and reaction of red phosphorus at 500 °C. The ring-shaped nanostructures with surrounding graphene walls are stable under ambient condi...
Easily available carbyne complexes of manganese were used as a source of carbyne fragments in an unconventional synthesis of backbone-substituted diphosphinomethanes and cyclic P-ylides upon coupling with secondary or tertiary phosphines, respectively, followed by demetalation under mild conditions.
Ugi adducts derived from aromatic aldehydes may be converted to pyrrolines via addition of Michael acceptors under microwave irradiation. The reaction may proceed via unusual formation of azomethine ylides followed by a [3+2] cycloaddition using Michael acceptors.
Straightforward deprotonation of soluble tetramethylammonium salts with alkyllithium reagents gives lithiomethyl trimethylammonium reagents. Coordination of the Li cation is crucial to the stability of these 'N-C ylides'. These reagents were used to prepare epoxides, aziridines and allylic alcohols.
Cycloaddition reactions between pyridinium ylides and 3-alkenyl oxindoles that proceed in high yield and with very good regio- and diastereoselectivity are reported. The resulting cycloadducts have the same stereochemistry of biologically active oxindole alkaloids, such as strychnofoline.
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