An asymmetric proline catalyzed aldol reaction with a-thioacetal aldehydes has been developed. Thioacetal bearing aldehydes readily participate as electrophilic cross-aldol partners with a broad range of aldehyde and ketone donors. High levels of reaction efficiency as well as diastereoand enantiocontrol are observed in the production of anti-aldol adducts. q 2004 Elsevier Ltd. All rights reser...

A series of domino reactions in which the intramolecular Schmidt reaction is combined with either a Sakurai reaction, an aldol reaction, or both is reported. The Sakurai reaction of an allylsilane with an azido-containing enone under Lewis acidic conditions followed by protonation of the resulting titanium enolate species allowed for a subsequent intramolecular Schmidt reaction. Alternatively, ...

Mannich reaction was applied between 4-fluorobezaldehyde, selected acetophenone and several anilines, catalyzed by silica sulfuric acid for the synthesis of β-amino carbonyl derivatives. Reaction time and yield of the products depended on the nature of acetophenone and aniline subsituents. Using aliphatic amines instead of aromatic amines under same reaction conditions, afforded aldol condensat...

A directed cross-aldol reaction of silyl enol ethers with carbonyl compounds, such as aldehydes and ketones, promoted by a Lewis acid, a reaction which is now widely known as the Mukaiyama aldol reaction. It was first reported in 1973, and this year marks the 40th anniversary. The directed cross-aldol reactions mediated by boron enolates and tin(II) enolates also emerged from the Mukaiyama labo...

SnoaL belongs to a family of small polyketide cyclases, which catalyse ring closure steps in the biosynthesis of polyketide antibiotics produced in Streptomyces. Several of these antibiotics are among the most used anti-cancer drugs currently in use. The crystal structure of SnoaL, involved in nogalamycin biosynthesis, with a bound product, has been determined to 1.35 A resolution. The fold of ...

meso-Functionalized dipyrromethanes 6-10 were synthesized by acid-catalyzed addition of pyrrole to αposition of 2-alkenyl pyrroles. The regiochemistry of the reaction can be explained by either the formation of more stable carbocation intermediate or β-addition of α,β-unsaturated carbonyl compounds. The starting 2alkenyl pyrroles were synthesized by Aldol condensation of 2-formylpyrrole with ac...

Abstract The Guerbet reaction is a possible way for transformation of ethanol to 1-butanol (important many kinds industries), which consists four steps: dehydrogenation, aldol condensation, dehydration, and hydrogenation. Due the elimination side-reactions, selective catalysis required favour production at temperature below 350 °C. main aim this work was via heterogeneous using active Mg–Al mix...

The first enantioselective catalytic direct cross-aldol reaction that employs nonequivalent aldehydes has been accomplished using proline as the reaction catalyst. Structural variation in both the aldol donor (R1 = Me, n-Bu, Bn, 91 to >99%) and aldol acceptor (R2 = I-Pr, I-Bu, c-C6H11, Et, Ph, 97-99% ee) are possible while maintaining high reaction efficiency (75-88% yield). Significantly, this...