allylation performed in aqueous media, an efficient synthesis of highly functionalized lactones was realized in good yields (64− 77%, Scheme 29). 238 However, the chirality installed during the first step almost had no influence on the second step, thus resulting in poor diastereoselectivity in the subsequent allylation reaction (1:1−2:1 dr).In situ formation of aldehyde from the oxidation of alcohol followed by one-pot indium-mediated allylation also provides an alternative method for the synthesis of homoallylic alcohol. Recently, Yadav and co-workers developed such a one-pot sequence by using chloramines-T (sodium salt of Nchlorotosylamide) as oxidant in the presence of a catalytic amount of FeCl 3 in CH 2 Cl 2 , giving rise to homoallylic alcohols in good to excellent yields (Scheme 30). 239 It is noteworthy that the generated byproduct of TsNH 2 (from the reduction of chloramines-T) may react with the in situ-formed aldehydes to give intermediates of N-tosylimines in the presence of 4 Å molecular sieve under refluxing; the thus-formed N-tosylimines subsequently underwent one-pot indium-mediated allylation to produce homoallylic amines in 60−80% yields. Later, a similar one-pot, two-step sequence for the synthesis of homoallylic alcohols via a galactose oxidase-mediated chemo-enzymatic oxidation of benzyl and cinnamyl alcohols to the corresponding Scheme 23 Scheme 24 Scheme 25 Scheme 26 Scheme 27 Scheme 28 Scheme 29 Scheme 30 Chemical Reviews Review dx.

Using α,α-difluoromethylene alkyne as a nontraditional one-carbon reaction partner, a synthetically novel method for the construction of isoindolin-1-one derivatives via Rh(III)-catalyzed [4+1] annulation reaction is reported. The 2-fold C-F bond cleavage not only enables the generation of desired product under an overall oxidant-free condition but also results in a net migration of carbon-carbon triple bond. In addition, the present reaction protocol exhibits a tolerance of a wide spectrum of functional groups due to the mild reaction conditions employed.

In this study, a remarkably simple and direct strategy has been successfully developed to selectively label target cysteine residues in fully unprotected peptides and proteins. The strategy is based on the reaction between allenamides and the cysteine thiol, and proceeds swiftly in aqueous medium with excellent selectivity and quantitative conversion, thus forming a stable and irreversible conjugate. The combined simplicity and mildness of the process project allenamide as robust and versatile handles to target cysteines and has potential use in biological systems. Additionally, fluorescent-labeling studies demonstrated that the installation of a C-terminal allenamide moiety onto various molecules of interest may supply a new methodology towards the site-specific labeling of cysteine-containing proteins. Such a new labeling strategy may thus open a window for its application in the field of life sciences.