Synthesis of D-erythro-sphingosine and D-erythro-ceramide.

A 1,2-metallate rearrangment of a higher order cuprate derived from an alpha-lithiated xylal derivative and tridecyllithium is the key step in a synthesis of D-erythro-sphingosine and ceramide. A convenient method for preparing alpha-lithiated glycals from alpha-phenylsulfinyl glycals is also described.

Synthesis of (S)-(-)-N-acetylcolchinol using intramolecular biaryl oxidative coupling.

An asymmetric synthesis of the tubulin polymerisation inhibitor (S)-(-)-N-acetylcolchinol is reported based on an intramolecular biaryl oxidative coupling of a 1,3-diarylpropyl acetamide intermediate using phenyliodonium bis(trifluoroacetate) as the final step. Three syntheses of the penultimate 1,3-diarylpropyl acetamide intermediate (S)-(-)-N-[1-[3-(tert-butyldimethylsilyloxy)phenyl)]-3-(3,4,5-trimethoxyphenyl)propyl] acetamide are described which differ in the means by which the stereogenic centre was introduced.

Synthesis of (+)-manoalide via a copper(I)-mediated 1,2-metalate rearrangement.

An enantiospecific synthesis of the phospholipase A(2) inhibitor (+)-(4R)-manoalide is reported in which all 25 carbons of the sesterterpenoid skeleton are constructed from 3-furaldehyde, trimethylalane, oxirane, CO, beta-ionone, and propargyl bromide. The overall yield for the longest linear sequence (12 steps) is 12%. Key steps include (a) a zirconium-catalyzed carboalumination reaction to construct the C10-C11 trisubstituted alkene, (b) a Cu(I)-mediated 1,2-metalate rearrangement to construct the C6-C7 trisubstituted alkene, (c) a Sharpless kinetic resolution to secure the (4R)-stereochemistry, (d) generation of a 5-stannyl-2,3-dihydrofuran by Mo-catalyzed cycloisomerization of a homopropargylic alcohol, and (e) construction of the hydroxyfuranone ring by photooxidation of a silylfuran.