Here, enzymes streamline synthesis by uniting small to medium-sized fragments of a larger target compound in an efficient manner -generally with excellent selectivity and without the need for any prefunctionalization or directing groups. As a testament to this prowess, the Narayan group recently employed P450 monooxygenases for crosscoupling reactions with coumarin-type phenols. In contrast to known organic or organometallic procedures, these P450 enzymes smoothly united different phenols, exerted surprising levels of atroposelectivity and proved highly amendable by protein engineering to improve their selectivity and substrate scope. In addition to such heterodimerization, the Sherman group reported the use of P450s for the asymmetric dimerization of diketopiperazines in the synthesis of naseseazine alkaloids. 27 Also employing radical transformations, the Sattley group used laccases to obtain pinoresinol analogues from coniferyl-type alcohols, which may serve as precursors to analogues of the topoisomerase inhibitor etoposide. In this example, the use of a dirigent protein provided nearly perfect stereocontrol in the dimerization of two planar units into a product featuring four vicinal stereocenters. Further complementing the work on Pictet-Spenglerases discussed above, the Hailes group recently explored their use in the convergent synthesis of isoquinoline scaffolds which could be elaborated by regioselective enzymatic methylation and chemical Pictet-Spengler reactions to obtain protoberberine alkaloids. Finally, the Merck team recently disclosed their catalytic route to the highly potent STING agonist MK-1454, a cyclic dinucleotide derived from guanosine and thymidine building blocks. The key convergent step unites two unusual, fluorinated thiophosphate nucleotides in a cascade comprising kinase-mediated phosphorylation and diastereoselective cyclization by a cyclic GMP-AMP synthase.