Nickel(0) triethyl phosphite complex-promoted reaction of allylic acetates with thiols produced allylic sulfides with retention of configuration without allylic rearrangement. A similar reaction of allylic acetates with alcohols and phenols also proceeded with retention of regio- and stereochemistry.

Combining three units of one of H-(alanyl)n-beta-(HO)alanyl peptides (n = 1-3) with nitrilotriacetic acid affords tripodal peptide hydroxamate ligands (1L, 1D, 2LL, 2DL, and 3LLL, where each L or D denotes the L- or D-alanyl residue). These ligands form six-coordinate octahedral complexes (Fe-1L, Fe-1D, Fe-2LL, Fe-2DL, and Fe-3LLL) with iron(III) in aqueous near neutral pH solution, and the stability and the chirality of the complexes formed depend on the alanyl residues incorporated. Thus Fe-2LL is the most stable against attack of H+ and OH- ions and the least labile in the iron(III) removal by EDTA. The CD spectra show a predominance of the A configuration for Fe-1D, Fe-2LL, Fe-2DL, and Fe-3LLL, but the opposite delta configuration for Fe-1L. These ligands and their gallium(III) complexes are studied by 1H NMR spectroscopy in DMSO-d6 solution. CD and NMR spectral analysis, aided by molecular model examinations, indicates that critical factors in controlling the configuration and the stability of the complexes are (1) the hydroxamate-carrying alanyl residue, (2) the expanse of an interior space in the ligand, and (3) an interstrand amide NH hydrogen bond; the latter bonding is possible with ligands 2LL and 2DL. A microbial growth promotion activity test shows that ligands 1L, 2LL, and 3LLL all act as iron-transporting agents.

[reaction--see text] The cyclic silyl ethers, 2,2-dimethyl-1-oxa-2-sila-3-cyclopentenes, were produced by the treatment of (Z)-gamma-trimethylsilyl allylic alcohols with a catalytic or stoichiometric amount of lithium tert-butoxide. On the other hand, successive treatment of the alcohols with copper(I) tert-butoxide and allylic halides followed by the tetrabutylammmonium fluoride assisted hydrolysis produced the allylation products, 2,5-alkadien-1-ols, with complete retention of configuration of the double bond.

Successive treatment of the (Z)-gamma-trimethylsilyl allylic alcohols with copper(I) tert-butoxide and allylic halides followed by the tetrabutylammonium fluoride-assisted hydrolysis produced the allylation products, 2,5-alkadien-1-ols, with complete retention of configuration. Similar treatment of the organometallic intermediates with aryl and vinylic halides in the presence of palladium(0) catalyst gave the corresponding cross-coupling products in good yields. The stereoselective preparation of the starting materials is also described.

The stereoselective alkenylation of unsaturated compounds by means of a (Z)-alkenyl sulfone-titanocene(II) system is described. Treatment of alkynes and (Z)-alkenyl methyl sulfones with the titanocene(II) reagent Cp2Ti[P(OEt)3]2 produced conjugated dienes. This alkenylation system is also applicable to polar C=O bonds; the simple mixing of carbonyl compounds, (Z)-alkenyl methyl sulfones, and the titanocene(II) reagent formed allylic alcohols. The advantages of alkenylation are that it requires no prepreparation of the alkenylmetal reagent and that it proceeds with complete stereoselectivity.

The front cover picture illustrates iodoarene as a precatalyst and dimethyl(fluoro)‐λ6‐sulfane as a real oxidant derived from DMSO and F‐TEDA‐PF6, and the Japanese kanji stands for the initial letters of key elements, sulfur, iodine, and fluorine. A hypervalent iodine(III) catalyst, generated in situ from these reagents, is effective on the dehydrogenative cycloisomerization/arylation reaction of N‐propargyl carboxamides and arenes. Details can be found in the Update by Saito and collaborators (Y. Umakoshi, Y. Takemoto, A. Tsubouchi, V. V. Zhdankin, A. Yoshimura, A. Saito, Adv. Synth. Catal. 2022, 364, 2053–2059; DOI: 10.1002/adsc.202200219)

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