Intramolecular (4+2) -Cycloadditions of Three Heterodienes: Nitrosoalkenes, Nitroalkenes, and Z-Alpha,beta-Unsaturated Aldehydes

Intramolecular (4+2) -cycloadditions employing nitrosoalkenes, nitroalkenes, and Z -α,β-unsaturated aldehydes as the 4π-components are discussed. Nitrosoalkenes, generated in situ from the corresponding α-chloroketone silyloximes, engaged in intramolecular cycloadditions with enol ethers and vinyl sulfides at ambient temperature. The yield and stereoselectivity of the tricyclic octahydronaphthalene (6-6)- and hexahydroindene (6-5)-oxazine cycloadducts varied. In the enol ether cases, the success of the cycloaddition depended on the olefin geometry. Only the dienophile bearing the proper geometry for secondary orbital overlap cyclized in high yield and with good stereoselectivity. The vinyl sulfides demonstrated no such geometry dependence and afforded high yields of cycloadducts in both 6-6 and 6-5 ring systems. Despite extensive effort, a general method for cleaving the cyloadducts could not be found.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Chemistry

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2014

Author dc:creator

• Sternberg, Jeffrey Arthur

• Chemistry, Organic

Identifier

(UMI)AAI8721766

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/70380