Prepackaged Ramberg–Bäcklund reagents: useful tools for organic synthesis

The synthesis and reactions of several α,β-unsaturated chloromethyl sulfones is presented, for example [(chloromethyl)sulfonyl]-1,3-propadiene (), [(chloromethyl)sulfonyl]ethene (), [(dichloromethyl)sulfonyl]ethene () and (E,Z)-1,2-bis[(chloromethyl)sulfonyl]ethene (). These compounds serve as ‘prepackaged’ Ramberg–Bäcklund reagents, which following an appropriate first step, such as Diels–Alder addition, react with base giving Ramberg–Bäcklund products.