Dedicated to Professor Dieter Enders on the occasion of his 70th birthday
Abstract
The title compound was prepared in a concise route starting from an appropriately
protected (S)-glyceraldehyde. A highly diastereoselective (d.r. >95:5) Mukaiyama aldol reaction
of an acetoacetate-derived silyl enol ether served as the initial step of the synthetic
sequence. It was found that protection of the glyceraldehyde as a butane-2,3-dione
acetal is required to achieve the desired diastereoselectivity. Upon lactonization,
a Tsuji–Trost allylation and a subsequent one-pot reaction cascade including an ozonolysis
and an α-hydroxylation gave diastereoselective access to the desired α-hydroxy-β-oxo-δ-lactone.
Alternative synthetic approaches are discussed and proof for the configuration of
the product is presented.
Key words
aldol reaction - diastereoselectivity - natural product synthesis - oxygenation -
polyketides