Tandem Cycloaddidon of Nitroalkenes

However, a-subsdnued dipolarophiles give poor selectivity and fi-siibstiriited dipolarophiles such dS methyl ci 

High-pressure promoted tandem [4-i-3 /[3-i-3 cycloadchdons of nitrostyrenes with enol ethers has been reported, which do not require the Lewis acids The products are converted into 

Asymmetnc tandem cycloaddicion of a chiral carbohydrate tutroalkene with ethyl vmyl ether in the ptesence of electron-withdrawmgalkenes produces a facile assembly of bicychc systems, which can further be seletnvely cleaved to give homologated carbohydrates fEq 8 110  

2 Intra [4+2]/inter [3+2] This type of tandem reaction nsmg nitroalkenes has n been extensively explored, and one example has been reported fEq 8 111  

The syntheac potenQ of the tandem [4+2 /[3+2 cycloadchtion process is greatly enhanced by the employment of vmyl ether dienophiles For example, the nse of vmyl bntyl ether as a chenophile leads to a tnoyclic nirroso acetal, which gives a tncyclic lactam, as shown m Eq 8113 

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