Modern powerful accelerators and composable infrastructures put our simulation frameworks to the test. We will show that the acceleration of a simulation framework is absolutely critical for good performance and scaling. Building on our previous work using research software as a benchmark for computing clusters, the High Performance Research Computing Group (HPRC)1 compares the Kokkos and GPU acceleration packages of LAMMPS (Large-scale Atomic/Molecular Massively Parallel Simulator) molecular dynamics software with NVIDIA H100 and Intel Data Center GPU Max 1100 accelerators on the composable ACES cyber-infrastructure at Texas A&M University. We observe different computational and communication patterns emerge from the different codes, which in turn result in different performance and scaling characteristics across these accelerators. We observe an opportunity for growth in the synergy between Intel’s oneAPI toolchain and the Kokkos framework to enable effective scaling of molecular dynamics simulations on composable infrastructure.

Spirocalcaridines A and B are among the most challenging members of the marine invertebrate-derived Leucetta alkaloids. Approaches to the construction and elaboration of the highly compact spirocyclic core are described. The synthesis of tricyclic guanidine via tandem oxidative amination dearomatizing spirocyclization (TOADS) using hypervalent iodine set the stage for total synthesis via the migration of the C4/C8 double bond to the C4/C5 position, followed by oxidation. The undesired but not surprising propensity of the spirocyclic cyclohexadienone to undergo rearrangement to the phenol hindered the desired olefin migration. Furthermore, initial efforts to install the oxidation sequentially, first at C5 and then at C4 in the complete carbon skeleton, were fraught with unforeseen challenges and unusual outcomes. In addition, the scope and limitations of hypervalent iodine-mediated tandem oxidative dearomatizing spirocyclization on various substrates were explored. Urethanes and thiourethanes underwent spirocyclization with an excellent yield, whereas the reaction with allylic substrates and species lacking the p-methoxy substituent did not proceed. Attempts to prepare other guanidine precursors are briefly discussed.

Spirocalcaridines A and B are among the most challenging members of the marine invertebrate derived Leucetta alkaloids. Approaches for construction and elaboration of the highly compact spirocyclic core are described. Synthesis of tricyclic guanidine via a tandem oxidative amination dearomatizing spirocyclization (TOADS) using hypervalent iodine set the stage for total synthesis via migration of the C4/C8 double bond to C4/C5 position followed by oxidation. The undesired but not surprising propensity of the spirocyclic cyclohexadienone to undergo rearrangement to the phenol hindered the desired olefin migration. Furthermore, initial efforts to install the oxidation sequentially first, at C5 followed by C4 of the complete carbon skeleton were fraught with unforeseen challenges and unusual outcomes. In addition, the scope, and limitations of hypervalent iodine mediated tandem oxidative dearomatizing spirocyclization on various substrates were explored. Urethanes and thiourethanes undergo spirocyclization in excellent yield whereas, the reaction with allylic substrates and species lacking the p-methoxy substituent does not proceed. Attempts to prepare other guanidine precursors are briefly discussed.