Alkylboronic esters are versatile, stereochemically rich building blocks, and numerous methods have been developed to access them. Among these, the 1,2-metallate rearrangement of vinylboronates has emerged as a powerful approach to 1,2-difunctionalize a vinyl group, furnishing complex alkylboron frameworks from simple starting materials. When carbon electrophiles are used, two new C-C bonds form in a single operation, enabling rapid assembly of highly functionalized products. To broaden the electrophile class, we proposed that highly reactive π-electrophiles could initiate the rearrangement and, at the same time, generate an anionic species for the next bond-forming event via π-bond cleavage. Guided by this idea, we developed (i) an aryne-triggered annulation and (ii) a ketene-triggered multicomponent coupling of simple vinylboronates. The strain of arynes and the polarized heterocumulene character of ketenes allow them to activate vinylboronates, trigger 1,2-metallate migration, and generate anionic intermediates that are trapped intramolecularly by a neighboring boronic ester or intermolecularly by external electrophiles. Here we describe the development, scope, limitations, and mechanistic features of these transformations.

Direct functionalization of inert C(sp³)-H bonds has long been considered one of the most challenging transformations in organic synthesis due to their high bond dissociation energies, low acidity, and poor orbital accessibility. Nevertheless, the ability to transform ubiquitous C(sp³)-H bonds without prefunctionalization offers significant advantages in atom economy, step efficiency, and structural diversification. In this study, radical generation and control were strategically utilized to develop efficient synthetic methods for various heterocyclic frameworks based on C(sp³)-H (and Si-H) bond functionalization.

Plants frequently rely on chemically mediated interactions—collectively known as allelopathy—to secure their ecological niche, and the small molecules involved in these processes often provide valuable leads for both biological studies and agrochemical development. Among such metabolites, cis-cinnamic acid, originally identified as the aglycone of cis-cinnamic acid glycosides from Spiraea thunbergii, exerts a pronounced effect on root growth. Motivated by this activity, our interdisciplinary team synthesized cis-cinnamic acid and a series of structural variants, ultimately creating a fluorescent derivative that enabled visualization of its preferential accumulation in the root cap.

Building on insights from its influence on gravitropic responses, we expanded our analogue library and identified ku-76 (2Z,4E-5-phenylpenta-2,4-dienoic acid) as a compound that selectively disrupts gravitropism. Further structure refinement using ku-76 as a starting point led to the development of BMA ((Z)-4-((Z)-benzylidene)-6-(4-methoxyphenyl)hex-2-en-5-ynoic acid), which displays markedly enhanced potency. In addition, we discovered mPCA (m-phenyl-cis-cinnamic acid), a highly potent and synthetically easily accessible inhibitor of gravitropism, through systematic exploration of cis-cinnamic acid analogues. Physiological assays suggest that these synthetic molecules interfere with the regulation of polar auxin transport, highlighting their potential as chemical tools for probing auxin-dependent signaling pathways.

This manuscript describes our strategy for developing stimuli-responsive molecular crystals through minimal transformations of known molecular skeletons. Rather than designing entirely new frameworks, we introduce small structural modifications to existing compounds and thereby create crystals showing new optical, mechanical, and phase-transition behaviors. In platinum isocyanide systems, arylation of halogenated precursors generates strongly emissive crystals with polymorphism, mechanochromism, crystal-to-amorphous transitions, and post-modification processes such as coproportionation and π-bridged dimerization. These examples show that simple molecular conversion can greatly expand crystal functionality. In benzodifuranone derivatives, bulky substituents suppress unfavorable face-to-face stacking and enable solid-state luminescence, mechanochromic responses, and thermosalient behavior. Furthermore, polymorphic benzodifuranone crystals exhibit photoregurated thermal phase transitions, leading to the unusual light-off salient effect, in which crystal motion occurs when irradiation is ceased. Overall, these studies demonstrate that organic synthesis can be used not only to make molecules, but also to design crystal packing, phase transitions, and macroscopic functions.

Metal-ligand cooperation is a powerful strategy to realize efficient and selective transformation and energy conversion. This review aims to provide an overview of the catalysis of pyrazole and protic N-heterocyclic carbene (pNHC) complexes as a new class of metal-ligand bifunctional catalysts. These ligands feature an acidic NH group at the β-position relative to the metal center. Such “β-protic” complexes often exhibit metal-ligand cooperative reactivity owing to the proton transfer at the NH group in the second coordination sphere, coupled with metal-centered events. In this review, some representative metal-ligand cooperative catalysts other than protic pyrazole and NHC complexes are first introduced. The following sections describe the hydrogenation and transfer hydrogenation as well as “borrowing hydrogen”-type carbon-carbon and carbon-nitrogen bond-forming reactions catalyzed by these β-protic complexes. Catalytic transformations independent of hydrogen-transfer processes are also discussed, including cyclization and annulation reactions.