Photoreductive cyclization: Application to the total synthesis of (±)-actinidine

Radical ion cyclizations

“…Due to the stereoselectivty and the mild conditions, the PETreductive cyclization reaction has been applied to the total synthesis of polycyclic and heterocyclic biologically active natural products such as ( + ) Hirsutene 180 [178,179] or ( _ ) Isooxyskyanthine 183 [180]. Further interesting applications have been reported by Cossy et al [181][182][183].…”

Pyrrolidine, piperidine, and pyridine alkaloids

“…African Conium spp., has been synthesized by a route starting with L-lysine and involving an anodic oxidation as key reaction (Scheme 4).,O A total synthesis of racemic prosafrinine (32), an alkaloid of the leaves of Prosopis africana, is outlined in Scheme 5 ; the final product was a mixture of 3-epimerides7 separable by HPLC. A 13C NMR analysis of (32) and related compounds was presented.21…”

“…A hydroxylated piperidine alkaloid (30) has been isolated from a small frog, Dendrobates speciosus, native to western Panama.18 Its structure is confirmed by an earlier synthesis effected before the compound was identified as a natural product.19 ( + )-N-Methylpseudoconhydrine (3 l), an alkaloid of S . African Conium spp., has been synthesized by a route starting with L-lysine and involving an anodic oxidation as key reaction (Scheme 4).,O A total synthesis of racemic prosafrinine (32), an alkaloid of the leaves of Prosopis africana, is outlined in Scheme 5 ; the final product was a mixture of 3-epimerides7 separable by HPLC. A 13C NMR analysis of (32) A review entitled ' Homochiral Compounds from Sugars ' demonstrates the relationship between hexoses and polyhydroxylated piperidine glycosidase inhibitors and summarizes syntheses of some jirimicins from them.23 A combined chemical and enzymic procedure for the synthesis of 1 -deoxynojirimycin (41) (occurring in plants of genus Morus) and l-deoxymannojirimycin (42) (occurring in Lonchocarpus pods) has been reported.…”

“…African Conium spp., has been synthesized by a route starting with L-lysine and involving an anodic oxidation as key reaction (Scheme 4).,O A total synthesis of racemic prosafrinine (32), an alkaloid of the leaves of Prosopis africana, is outlined in Scheme 5 ; the final product was a mixture of 3-epimerides7 separable by HPLC. A 13C NMR analysis of (32) A review entitled ' Homochiral Compounds from Sugars ' demonstrates the relationship between hexoses and polyhydroxylated piperidine glycosidase inhibitors and summarizes syntheses of some jirimicins from them.23 A combined chemical and enzymic procedure for the synthesis of 1 -deoxynojirimycin (41) (occurring in plants of genus Morus) and l-deoxymannojirimycin (42) (occurring in Lonchocarpus pods) has been reported. The key step is the fructose 1,6-diphosphate aldolasecatalysed aldol condensation between dihydroxyacetone monophosphate (39) and the azidoaldehyde (40), which yields an epimeric mixture of triols.…”

Intramolecular Ketone−Nitrile Reductive Coupling Reactions Promoted by Samarium(II) Iodide

“…Carbonyl coupling reactions passing through a ketyl intermediate constitute an important class of reactions in organic chemistry. Samarium(II) iodide (SmI 2 ) has been shown to promote a wide variety of these reactions, including ketyl−olefin couplings and intramolecular pinacolic coupling reactions. 1b,c,e Ketyl formation can also be achieved with other reductants 1d, and by electrochemical and photochemical processes . The high degree of chemoselectivity exhibited by SmI 2 , however, provides several advantages over the aforementioned methods.…”