STEREOSELECTIVE CONJUGATE ADDITION DIRECTED BY AN ENANTIOMERICALLY PURE KETAL - PREPARATION OF THE CYCLOHEXANONE FRAGMENT OF N-METHYLWELWITINDOLINONE-C-ISOTHIACYANATE
Jp. Konopelski et al., STEREOSELECTIVE CONJUGATE ADDITION DIRECTED BY AN ENANTIOMERICALLY PURE KETAL - PREPARATION OF THE CYCLOHEXANONE FRAGMENT OF N-METHYLWELWITINDOLINONE-C-ISOTHIACYANATE, Synlett, (10), 1998, pp. 1105
A cyclohexanone intermediate to be employed in the synthesis of the ma
rine natural product N-methylwelwitindolinone C isothiocyanate has bee
n prepared. The synthesis is diastereoselective for the production of
the C12 quaternary center, which is obtained via a conjugate addition
reaction directed by an adjacent chiral, nonracemic ketal. A single cr
ystal X-ray analysis of a derivative of the final product established
the absolute stereochemistry at C12.