Reduced density matrix functional theory (RDMFT), a promising direction in the problem of describing strongly correlated systems, is currently limited by its explicit dependence on natural orbitals and, by extension, the costly need to construct two-electron integrals in the molecular orbital basis. While a resolution-of-the-identity approach can reduce the asymptotic scaling behavior from O(N 5) to O(N 4), this is still prohibitively expensive for large systems, especially considering the usually slow convergence and the resulting high number of orbital optimization steps. In this work, efficient integral-direct methods are derived and benchmarked for various approximate functionals. Furthermore, we show how these integral-direct methods can be integrated into existing self-consistent energy minimization frameworks in an efficient manner, including improved methods for calculating diagonal elements of the two-electron integral tensor as required in self-interaction-corrected functionals and second derivatives of the energy with respect to the occupation numbers. In combination, these methods provide speedups of up to several orders of magnitude while greatly diminishing memory requirements, enabling the application of RDMFT to large molecular systems of general chemical interest, such as the challenging triplet–quintet gap of the iron­(II) porphyrin complex.

An alternative and complementary transformation for the synthesis of aryl- and heteroaryl-substituted alkynes is presented that relies on a chemoselective electrocoupling process. Tetraorganoborate substrates were logically designed and simply accessed by transmetalations using readily or commercially available organotrifluoroborate salts.

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Chiral β‐aminoalkylzinc halides were prepared starting from optically pure commercial β‐amino‐alcohols. These amino‐alcohols were converted to the corresponding N ‐pyrrolyl‐protected alkyl iodides which undergo a zinc insertion in the presence of LiCl (THF, 25 °C, 10–90 min). Subsequent Negishi cross‐coupling or acylation reactions with acid chlorides produced amino‐derivatives with retention of chirality. Diastereoselective CBS‐reductions of some prepared N ‐pyrrolyl‐ketones provided 1,3‐subsituted N ‐pyrrolyl‐alcohols with high diastereoselectivity. Additionally, a deprotection procedure involving an ozonolysis allowed the conversion of the pyrrole‐ring into a formamide without loss of optical purity.