(+)-(R,Z)-5-Muscenone and (-)-(R)-muscone by enantioselective aldol reaction and Grob fragmentation.

(+)-(R,Z)-5-Muscenone ((R)-1) was synthesized by an enantioselective aldol reaction, catalyzed by new ephedrine-type Ti reagents (up to 70 % enantiomeric excess). Substrate-directed diastereoselective reduction of the aldol product and Grob fragmentation of the tosylate of the resultant 1,3-diol afforded (+)-1. This approach also gave access to (-)-(R,E)-5-muscenone and (-)-(R)-muscone.

Synthesis of functionalized oxazolones by a sequence of Cu(II)- and Au(I)-catalyzed transformations.

A study concerning a two-step sequence leading to the formation of diversely 1,5-disubstituted oxazolones is described. The mild conditions employed allow the efficient and rapid synthesis of a variety of such compounds via an initial Cu(II)-catalyzed coupling of a bromoalkyne with a secondary tert-butyloxycarbamate followed by a Au(I)-catalyzed cycloisomerization of the N-alkynyl tert-butyloxycarbamates thus obtained.

Gold(I)-catalyzed isomerization of allenyl carbinol esters: an efficient access to functionalized 1,3-butadien-2-ol esters.

A study concerning the gold(I)-catalyzed rearrangement of diversely substituted allenyl carbinol esters into functionalized 1,3-butadien-2-ol esters is described. The mild conditions employed allow the efficient, rapid, and stereoselective synthesis of a variety of such compounds via a new 1,3-shift of an ester moiety onto a gold-activated allene. [structure: see text]