Generation and Application of Homoallylic α,α-Diboryl Radicals via Diboron-Promoted Ring-Opening of Vinyl Cyclopropanes: cis-Diastereoselective Borylative Cycloaddition.

Carbon-centered radicals stabilized by adjacent boron atoms are underexplored reaction intermediates in organic synthesis. This study reports the development of vinyl cyclopropyl diborons (VCPDBs) as a versatile source of previously unknown homoallylic α,α-diboryl radicals via thiyl radical catalyzed diboron-directed ring opening. These diboryl stabilized radicals underwent smooth [3+2] cycloaddition with a variety of olefins to provide diboryl cyclopentanes in good to excellent diastereoselectivity.

Planning Implications Related to Sterilization-Sensitive Science Investigations Associated with Mars Sample Return (MSR).

The NASA/ESA Mars Sample Return (MSR) Campaign seeks to establish whether life on Mars existed where and when environmental conditions allowed. Laboratory measurements on the returned samples are useful if what is measured is evidence of phenomena on Mars rather than of the effects of sterilization conditions. This report establishes that there are categories of measurements that can be fruitful despite sample sterilization and other categories that cannot.

Preliminary Planning for Mars Sample Return (MSR) Curation Activities in a Sample Receiving Facility (SRF).

The Mars Sample Return Planning Group 2 (MSPG2) was tasked with identifying the steps that encompass all the curation activities that would happen within the MSR Sample Receiving Facility (SRF) and any anticipated curation-related requirements. An area of specific interest is the necessary analytical instrumentation. The SRF would be a Biosafety Level-4 facility where the returned MSR flight hardware would be opened, the sample tubes accessed, and the martian sample material extracted from the tubes.

Science and Curation Considerations for the Design of a Mars Sample Return (MSR) Sample Receiving Facility (SRF).

The most important single element of the "ground system" portion of a Mars Sample Return (MSR) Campaign is a facility referred to as the Sample Receiving Facility (SRF), which would need to be designed and equipped to receive the returned spacecraft, extract and open the sealed sample container, extract the samples from the sample tubes, and implement a set of evaluations and analyses of the samples. One of the main findings of the first MSR Sample Planning Group (MSPG, 2019a) states that "The scientific community, for reasons of scientific quality, cost, and timeliness, strongly prefers that as many sample-related investigations as possible be performed in PI-led laboratories outside containment." There are many scientific and technical reasons for this preference, including the ability to utilize advanced and customized instrumentation that may be difficult to reproduce inside in a biocontained facility, and the ability to allow multiple science investigators in different labs to perform similar or complementary analyses to confirm the reproducibility and accuracy of results.