US chemists have developed an easy, direct route to a class of small, strained organic molecules that could be used in drug discovery.

Richard Hsung and colleagues, at the University of Wisconsin, Madison, reacted zinc carbenoids with allenamides  - a method known as Simmons-Smith cyclopropanation - to make amino-spiro[2,2]pentanes. Amino-spiro[2,2]pentanes are useful for a range of biological and medicinal studies, such as constructing deoxyribonucleotide analogues, but scientists have put little effort into finding good ways to make them, says Hsung. The Simmons-Smith method is efficient and general and is the most direct route to these chemically and biologically interesting compounds, he claims.

'While we were unable to attain high levels of diastereoselectivity, and while both diastereomers would be of interest in the context of biological studies, we intend to resolve this issue through examining an array of available asymmetric cyclopropanation tools,' comments Hsung.