Schmoggi

Nature Chemistry, Published online: 07 September 2020; doi:10.1038/s41557-020-0539-8

A six-helix bundle DNA structure called meta-DNA has now been assembled and shown to possess some structural properties similar to those of single-stranded DNA. Two meta-DNAs containing complementary ‘meta-base pairs’ are shown to form double helices. Meta-DNA building blocks are also used to construct a series of DNA architectures and to perform a hierarchical strand-displacement reaction.

The first general approach to the formation of enantioenriched cyclopropanone equivalents is reported by the α‐hydroxylation of sulfonylcyclopropanes, giving access to a wide variety of highly reactive and modular reagents suitable for ring‐expansion processes. Exemplified here is the formation of chiral β‐lactams by a formal [3+1] cycloaddition using simple hydroxylamines as nitrene sources.

Abstract

Cyclopropanone derivatives have long been considered unsustainable synthetic intermediates because of their extreme strain and kinetic instability. Reported here is the enantioselective synthesis of 1‐sulfonylcyclopropanols, as stable yet powerful equivalents of the corresponding cyclopropanone derivatives, by α‐hydroxylation of sulfonylcyclopropanes using a bis(silyl) peroxide as the electrophilic oxygen source. This work constitutes the first general approach to enantioenriched cyclopropanone derivatives. Both the electronic and steric nature of the sulfonyl moiety, which serves as a base‐labile protecting group and confers crystallinity to these cyclopropanone precursors, were found to have a crucial impact on the rate of equilibration to the corresponding cyclopropanone. The utility of these cyclopropanone surrogates is demonstrated in a mild and stereospecific formal [3+1] cycloaddition with simple hydroxylamines, leading to the efficient formation of chiral β‐lactam derivatives.