High-Pressure Domino Cycloaddition Reactions on the Solid Phase

The diversity of this novel domino reaction can be further increased by using different dipolarophiles. 

High-Pressure Domino [4 -h 2]/[3 -h 2] Cycloaddition Reactions on the Solid Phase 

The solid phase synthesis of nitroso acetals via a resin-bound dipolarophile will be described first. It has already been mentioned that nitronates react much faster with electron-poor alkenes than with electron-rich alkenes. The reaction of the nitronate formed in situ with the resin-bound acrylate is therefore expected to be faster than its reaction with the enol ether in solution. An acrylate was selected as dipolarophile and coupled to the resin via an ester linkage, which allows the facile cleavage of the resin-bound nitroso acetals by several methods (hydrolysis, reduc- 

4 Yields of purified cycloadducts based on initial loading level of the Wang Resin (1.22 mmol g ). 

The cycloadducts 69a-f were isolated as mixtures of diastereomers. Yields after a three-step reaction sequence were reasonable (33-52 % not optimized [29]), even in the case of higher substituted enol ethers and nitrostyrenes (Table 9.2). 

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