Intramolecular Photocycloaddition of Unsaturated Isoquinuclidines. Synthesis of 2-Azatetracyclo[4.0.0.4,907,10]decanes and 3-Azatetracyclo[6.1.1.0.2,705,9]decanes

• Published in: Journal of organic chemistry Vol. 69; no. 11; pp. 3758 - 3764
• Main Authors: Choi, Younggi, White, James D
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 28-05-2004
• Subjects: Chemistry; Cyclization; Exact sciences and technology; General and physical chemistry; Heterocyclic compounds; Heterocyclic compounds with only one n hetero atom and condensed derivatives; Molecular Structure; Organic chemistry; Photochemistry; Physical chemistry of induced reactions (with radiations, particles and ultrasonics); Preparations and properties; Quinuclidines - chemical synthesis; Reaction intermediate; Intramolecular reaction; Isoquinoline derivatives; Nitrogen heterocycle; Diels Alder addition; Tetracyclic compound; Photochemical reaction; Dienic compound; Unsaturated compound; Cycloaddition; Organic free biradical; Bicyclic compound; Dihydropyridine derivatives; Ethylenic compound; Nicotinic acid derivatives
• ISSN: 0022-3263; 1520-6904
• DOI: 10.1021/jo0401321

2-Azabicyclo[2.2.2]oct-5-enes bearing an endo alkenyl substituent were synthesized by Diels−Alder addition of methyl vinyl ketone to a 1,6-dihydropyridine derived from methyl nicotinate. Although 1,5-dienes with this skeleton were unreactive under thermal conditions, they were photochemically reactive. Irradiation of these dienes through a Corex filter resulted in intramolecular [2 + 2] cycloaddition to give “parallel” and “crossed” photoadducts along with small amounts of a hexahydroisoquinoline. The latter is thought to represent leakage of a diradical intermediate responsible for the parallel photoadduct. The new 2-azatetracyclo[4.4.0.0.4,907,10]decane and 3-azatetracyclo[6.1.1.0.2,705,9]decane structures formed in the photochemical reactions are thermally stable.