Stereocontrolled construction of the A-ring of nitiol using a Pauson-Khand cycloaddition-ring fragmentation strategy.

[reaction: see text] A stereocontrolled construction of the A-ring of nitiol (1) is presented. Key features in this approach are a diastereoselective Pauson-Khand cycloaddition and a Norrish type 1 fragmentation reaction.

Construction of azaspirocyclic ketones through alpha-hydroxyiminium ion or alpha-siloxy epoxide semipinacol rearrangements.

[reaction: see text] Semipinacol-type rearrangements to produce azaspirocyclic ketones are presented. The yields and stereoselectivities of these reactions range from 67-94% yield and 2.8:1 to 1:0 diastereoselectivity, respectively.

The first stereoselective total synthesis of quinine.

The first entirely stereoselective total synthesis of (-)-quinine is reported.