The Type 2 Intramolecular Diels-Alder Reaction. Tether is attached to the 1 position of the diene Leads to fused bicycles. Tether is attached to the 2 position of the diene Leads to bridged bicycles with bridgehead double bonds Tether can control regioselectivity, stereoselectivity, and - PowerPoint PPT Presentation
The Type 2 Intramolecular Diels-Alder Reaction
Tether is attached to the 1 position of the diene Leads to fused bicycles Tether is attached to the 2 position of the diene Leads to bridged bicycles with bridgehead double bonds Tether can control regioselectivity, stereoselectivity, and
Hetero Type 2 Diels-Alder Reactions
Previous work in the area of hetero type 2 Diels-Alder reactions has shown N-acyl
imines to participate in the Diels-Alder reaction to provide bridgehead amides.1
Current studies are looking to expand the scope of the type 2 hetero intramolecular
The use of a more reactive hetero dienophile is being investigated.
Type 2 Intramolecular Nitroso Diels-Alder Reactions
The type two intramolecular Diels-Alder cycloaddition of N-acylnitroso dienophiles
is currently being studied for the synthesis of bridged [n,3,1] oxazinolactams.
In situ oxidation of hydroxamic acids provide N-acyl nitroso dienophiles which
undergo cycloaddition to provide 3,6 dihydro-1,2 oxazines.
These cycloadducts can subsequently be transformed into medium ring amides
Synthesis of Precursor Hydroxamic Acids
Synthesis of Bridged [n,3,1] Oxazinolactams
9, 10-Dimethylanthracene Adducts
Regiochemistry of T2IMNDA
Measuring Bridgehead Olefin Distortion
Two parameters, and , are used to quantify the degree of distortion in a strained olefin.2 , which represents the angle between the p-orbitals of a bond, is measured by
= (1 + 2)/2 shown in composite structure V.
, the pyramidalization angle of the constituent atoms of the system, is defined as the
acute angle formed by the projection of one substituent (Z) across the atom onto the
geminal substituent (Y). For an sp2.00 atom, = 0.0, while for an sp3.00 atom, =60.0.
X-Ray Crystal Structures
Parameter 4 5
Functionalization of Bridged Oxazinolactams
Work in Progress
References and Acknowledgements
1. The Type 2 Intramolecular Imino Diels-Alder Reaction. Synthesis and Structural Characterization
Of Bicyclo [n,3,1] Bridgehead Olefin/Bridgehead Lactams. Shea, K.J., Lease, T.G.: J. Am. Chem.
Soc. 1993, 115, 2248
2. Winkler, F. K.: Dunitz, J. D. J. Mol. Biol. 1971, 59, 169-182.
Financial Support of this work from the Undergraduate Research Opportunities Program is
Financial Support of this work from Allergan is gratefully acknowledged. Travel Funding from the UCI CAMP program is gratefully acknowledged.