ABSTRACT
An efficient Lewis acid induced nitrogen-driven rearrangement iminium-trapping cascade from an epoxytropinone 3 gives a 7-allylated 6-azabicyclo[3.2.1]octan-3-one 2, which is converted into the alkaloid (+/-)-peduncularine (1).
Subject(s)
Alkaloids/chemical synthesis , Azabicyclo Compounds/chemistry , Indole Alkaloids/chemical synthesis , Octanes/chemistry , Alkaloids/chemistry , Indole Alkaloids/chemistry , Molecular Structure , StereoisomerismABSTRACT
Heteroaromatic 2-pyridyl tosylates were successfully applied as electrophiles in palladium(0)-catalyzed Mizoroki-Heck-coupling reactions to electron-rich olefins with complete alpha-regioselectivity. This protocol represents a general strategy for the application of pyridyl tosylates and mesylates in the Mizoroki-Heck coupling. The catalytic system also proved adaptable to changes in the heteroaromatic core as well as large-scale applications. Finally, the synthetic utility of the functionalized alpha-heteroarylvinyl amides was established providing straightforward access to highly functionalized heteroaromatic compounds including chiral benzylic amide derivatives.
Subject(s)
Alkenes/chemistry , Benzyl Compounds/chemical synthesis , Heterocyclic Compounds/chemical synthesis , Tosyl Compounds/chemistry , Benzyl Compounds/chemistry , Electrons , Heterocyclic Compounds/chemistry , Molecular Structure , Palladium/chemistry , StereoisomerismABSTRACT
[reaction: see text] A multicomponent synthesis of 4-imino-4H-3,1-benzoxazines is developed. Heating a toluene solution of an aldehyde (6), an amine (7), and an isonitrile (5) in the presence of a stoichiometric amount of ammonium chloride at 60 degrees C for 12 h produces the title compound in good to excellent yields.
ABSTRACT
One-carbon homologation of aldehyde into amide is realized in one-pot by its reaction with potassium alpha-p-methoxyphenyl-alpha-isocyano acetic acid (1c) and hydrochloride salt of dimethylamine (3a) in toluene at room temperature followed by acidic workup. In this multicomponent reaction, 1c served as donor of the CONH2 function to aldehyde, while the dimethylamine acted as a shuttle molecule to initiate/terminate the sequence and to mediate the internal redox process of one of the three-component adducts. Ready accessibility, nominal cost of the reagents, and mild conditions are attractive features of the present method.
ABSTRACT
[reaction: see text] Conditions have been developed for the multicomponent synthesis of di- and tetrapeptide (7) based on the unique reactivity of alpha-isocyano acetic acid (4 and its alpha-substituted derivatives) by an Ugi four-component, five-center reaction. Simply mixing 4, a carbonyl compound (aldehyde or ketone, 8), and a secondary amine (9) (ratio: 1:1:2) in toluene in the presence of 1.5 equiv of ammonium chloride afforded the desired product in good to excellent yield as a mixture of two diastereomers.
