Shuji Akai 교수

Mix and match: A new type of dynamic kinetic resolution of racemic allyl alcohols uses a combination of lipases and [VO(OSiPh3)3] (1). The 1,3-transposition of allyl alcohols catalyzed by 1 gave thermodynamic mixtures of two regioisomers, which underwent highly enantio- and chemoselective esterification with lipases. Optically enriched allyl acetates were isolated in high yields.

The combination of vanadium-oxo compounds (3 or 4) with a lipase produced the regio- and enantioconvergent transformation of racemic allyl alcohols (1 or 2) into optically active allyl esters. In this system, the vanadium compounds catalyzed the continuous racemization of the alcohols along with the transposition of the hydroxyl group, while the lipase effected the chemo- and enantioselective esterification to achieve the dynamic kinetic resolution.

V for resolution: A new oxovanadium catalyst (V-MPS; see scheme) immobilized in the pores of mesoporous silica has been developed. The combined use of V-MPS and lipases achieved the dynamic kinetic resolution of a wide range of racemic alcohols (1 or 2) to produce optically active esters 3 in high chemical and optical yields. The paired catalysts retained high catalytic activity when reused up to six times.

Two for the price of one: A method has been developed for the regiocontrolled synthesis of multisubstituted biaryl derivatives. This protocol involves the use of the tert-butyldimethylsilyl (TBDMS) group to direct the regioselective Diels–Alder reaction of a 3-TBDMS-benzyne with a furan derivative and a subsequent Hiyama cross-coupling reaction of the TBDMS group with aryl iodides (see scheme).

We have discovered that the racemization of configurationally stable, axially chiral 2,2'-dihydroxy-1,1'-biaryls proceeds with a catalytic amount of a cyclopentadienylruthenium(II) complex at 35-50 °C. Combining this racemization procedure with lipase-catalyzed kinetic resolution led to the first lipase/metal-integrated dynamic kinetic resolution of racemic axially chiral biaryl compounds. The method was applied to the synthesis of various enantio-enriched C₁ - and C₂ -symm

A wide range of aryl boronic 1,1,2,2-tetraethylethylene glycol esters [ArB(Epin)s] were readily synthesized. Purifying aryl boronic esters by conventional silica gel chromatography is generally challenging; however, these introduced derivatives are easily purified on silica gel and isolated in excellent yields. We subjected the purified ArB(Epin) to Suzuki-Miyaura couplings, which provided higher yields of the desired biaryl products than those obtained using the corresponding aryl boronic acids

Combining chemistry: The use of a lipase and a ruthenium catalyst allows the direct preparation of polysubstituted decalines with high optical and chemical yields from racemic alcohols (see scheme). The lipase-catalyzed kinetic resolution of the racemic alcohols, the ruthenium-catalyzed racemization of the slow-reacting enantiomers, and an intramolecular Diels–Alder reaction of the resultant esters all occur under identical conditions. Supporting information for this article is available on the

[reaction: see text] The reactions of (phenylsulfinyl)furans or -thiophenes with carbon nucleophiles in the presence of trifluoroacetic anhydride allowed the nucleophilic installation of carbon functional groups on the furan and thiophene nuclei with complete regioselectivity.

Double or nothing: In a convergent synthesis of the title compound, a potent inhibitor of human telomerase, two different aromatic Pummerer-type reactions were employed to construct the pivotal bisbenzannelated spiroketal skeleton from the two fragments shown in the scheme. This methodology offers convenient access to a wide range of substituted bisbenzannelated spiroketals from naphthol derivatives. MOM=methoxymethyl.

Cause and effect: The first ortho-selective nucleophilic addition reaction of amines to 3-substituted benzynes has been achieved. Despite a large trimethylsilyl substituent, primary amines attack the C2 position of 3-silylbenzynes to produce 2-silylanilines (see scheme). This outcome is likely to result from the inductive electron-donating effect of the silyl group, which overrides its steric repulsion with the approaching amines.

We have devised a novel 1,3-benzdiyne equivalent, capable of quadruple functionalization by sequential benzyne generation and reaction with arynophiles. The key features of this method include the chemoselective generation of two triple bonds in a single benzene ring under fluoride-mediated mild conditions, and the regiocontrol of each benzyne reaction by the substituent next to the triple bond. This method produced various benzo-fused heteroaromatic compounds <i>via</i> reactions with arynophil

Both enantiomers of oxindoles 2a-h, having a stereogenic quaternary carbon center at the C3 position and a different N-protective group, were readily prepared by the lipase-catalyzed desymmetrization protocol. Thus, the transesterification of the prochiral diols 3a-h with 1-ethoxyvinyl 2-furoate 5 was catalyzed by Candida rugosa lipase to give (R)-(+)-2a-h (68-99% ee), in which the use of a mixed solvent, (i)Pr(2)O (diisopropyl ether)-THF, was crucial. The same lipase also effected the enantiose

A convergent synthesis of diversely substituted benzofuran neolignans (8) is described employing a single p-sulfinyl group on the phenols (3) as an ambident functional group for two types of carbon-carbon bond-forming reactions: (i) the direct synthesis of the dihydrobenzofuran skeletons through an aromatic Pummerer-type reaction and (ii) the ipso-substitution of the sulfur functional group by carbon substituents through a ligand exchange reaction.