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We have developed a new umpolung strategy for catalytically forming a chiral α-alkoxyalkyl anion from an aromatic aldehyde for use in asymmetric synthesis. The reaction between aromatic aldehydes and aryl or allyl electrophiles with a silylboronate utilizing a chiral copper−N-heterocyclic carbene catalyst and a palladium−bisphosphine catalyst in a synergistic manner occurred with high enantioselectivities to deliver the three-component coupling products, chiral silyl-protected secondary alcohol derivatives. Our method features the catalytic generation of enantioenriched chiral αalkoxyalkylcopper(I) intermediates from aldehydes and their subsequent palladium-catalyzed stereospecific crosscoupling.

A new lanthanoid porous coordination polymer, La-BTTc (BTTc = benzene-1,3,5-tris(2-thiophene-5-carboxylate)), was synthesized and structurally characterized to have densely aligned one-dimensional open metal sites, which were found to act as strong Lewis acid sites after the removal of the coordinated solvent.

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Stable 1,2-bis(metallocenyl)disilenes were synthesized for the first time and were characterized by spectroscopic and X-ray crystallographic analyses. On the basis of cyclic voltammograms, (E)-1,2-bis(ferrocenyl)-1,2-bis(2,4,6-triisopropylphenyl)disilene (1a) was found to be a stable five-electron redox system with four steps, while (E)-1,2-bis(ruthenocenyl)-1,2-bis(2,4,6-triisopropylphenyl)disilene (1b) showed four-step redox couples with four electrons. The UVvis spectra and theoretical calculations for these disilenes suggested that they should be novel d³ conjugated systems containing a disilene unit. In addition, chalcogenation reactions of 1a resulted in the formation of new heterocyclic compounds bearing ferrocenyl units. For example, the first stable 1,2,3,4-dithiadisiletane derivative was obtained by the sulfurization reaction of 1a.Organic compounds containing ³-electron systems such as ethylene, benzene, and ketones are of great importance. Especially, extended ³-electron-conjugated systems of organic compounds exhibit lower HOMOLUMO gaps than those of olefins, showing unique electronic character and possibly applicable to semiconductors, organic electroluminescence, and so on.1 On the other hand, ferrocene is known to show unique electrochemical properties as a stable redox system. 2 d³ Electron-conjugated systems, e.g., multinuclear transitionmetal complexes bridged by organic ³-conjugated systems such as phenylene and C=C units, have attracted considerable attention from the viewpoint of their electrochemical properties.3 Particularly, stable multistep redox systems should be good model systems for the elucidation of the properties of mixed-valence states.4 Therefore, there has been much interest in the chemistry of ferrocene oligomers bearing a ³-electron spacer, e.g., Fc(Ph)C=C(Ph)Fc, 5 FcN=NFc, 6 and TbtP=PFc (Fc = ferrocenyl), 7 as models of mixed-valence states (Figure 1).The first stable disilene as a novel ³-bond system between two silicon atoms was synthesized and isolated by West and his co-workers in 1981. 8 Since disilenes are highly reactive due to the weak ³ bond between silicon atoms, kinetic stabilization should be necessary to isolate and handle disilene derivatives.

Hydrosilanes act as a reagent to cleave the C–O bond of OtBu groups in carbamates, carbonates, esters, and ethers by catalysis of a triruthenium cluster. The reaction offers a novel deprotection method for OtBu groups under neutral conditions, showing unique selectivities that have never been accomplished with conventional Brønsted or Lewis acidic promoters. Possible mechanisms for C–O cleavage are discussed on the basis of NMR spectroscopic analysis.

A new type of disilene substituted by ferrocenyl groups, 1,2-bis(ferrocenyl)disilene, was synthesized as a good candidate for a noVel d-π electron system, and the unique properties of the SidSi π bond of this new disilene were reVealed. On the basis of the results of the electrochemical analyses, 1,2-Tip 2 -1,2-Fc 2 -disilene (Tip ) 2,4,6-triisopropylphenyl, Fc ) ferrocenyl) was found to be a stable fiVe-electron redox system with four steps.