Enantiospecific total synthesis of (+)-laevigatin

Enantioselective Copper‐Catalyzed Conjugate Addition of Trimethylaluminum to β,γ‐Unsaturated α‐Ketoamides: Efficient Access to γ‐Methyl‐Substituted Carbonyl Compounds

“…Finally, Friedel-Crafts acylation gave the desired tetralone 6 with 99.5 % ee. This tetralone is, for example, an intermediate in the total synthesis of (À)-laevigatin, [14] (S)-ar-himachalene, [15] and (+)-erogorgiaene. [16] Starting from A1, we also considered the possibility of accessing acyclic natural compounds.…”

Enantioselective Iridium‐Catalyzed Hydrogenation of β,γ‐Unsaturated Carboxylic Acids: An Efficient Approach to Chiral 4‐Alkyl‐4‐aryl Butanoic Acids

“…Optically active 4‐alkyl‐4‐aryl butanoic acids 1 are generally prepared from chiral materials by means of multistep transformations 1b–e,k. The transition‐metal‐catalyzed asymmetric hydrovinylation of alkenes,1a hydrogenation of α,β‐unsaturated carboxylic acids,1f isomerization of allylic alcohols,1j and some enzymatic catalytic methods1h,i have all been used to construct a chiral benzyl center, but a subsequent multistep transformation is required to obtain the target 4‐alkyl‐4‐aryl butanoic acids 1 .…”

“…With the hydrogenation product 1 i as starting material, ( R )‐aristelegone‐A,7 was obtained through a Brønsted acid catalyzed Friedel–Crafts acylation and a subsequent demethylation with Et 2 NCH 2 CH 2 SNa in 68 % overall yield (steps a and b). Note that the present procedure is a novel and general route for the construction of tetralones with a chiral benzyl center, a core structure for diverse natural products 1a,d,f,g,k. The ( R )‐curcumene8 and ( R )‐xanthorrizol,9, 10 were synthesized from the hydrogenation products 1 b and 1 i respectively.…”

Enantioselective Copper‐Catalyzed Conjugate Addition of Trimethylaluminum to β,γ‐Unsaturated α‐Ketoamides: Efficient Access to γ‐Methyl‐Substituted Carbonyl Compounds

“…Finally, Friedel–Crafts acylation gave the desired tetralone 6 with 99.5 % ee . This tetralone is, for example, an intermediate in the total synthesis of (−)‐laevigatin,14 ( S )‐ ar ‐himachalene,15 and (+)‐erogorgiaene 16…”