Diisopropylethylamine , acyl derivative

Asymmetric Catalysts Using Sc(OTf)3. The chiral Sc catalyst prepared from Sc(OTf)3, (i )-BINOL, and a tertiary amine in dichloromethane (eq 22) serves as an asymmetric catalyst for the Diels-Alder reactions of an acrylic acid derivative with dienes (eq 23). The highest enantioselectivities are observed when di -l,2,6-trimethylpiperidine is employed as the amine. Even 3 mol % of the catalyst is enough to complete the reaction yielding the endo adduct in 92% ee. The structure of the chiral Sc catalyst is indicated by C-NMR and IR spectra. A similar Sc(OTf)3/(R)-BINOL/diisopropylethylamine complex serves as an effective catayst for the Diels-Alder reaction of A-benzyloxy-carbonyl-l-aminobutadiene with 3-acyl-l,3-oxazolidin-2-one. ... 

It is often simpler to modify the sequence in eq 16 to a sequence in which the resin-bound sulfenyl thiocarbonate intermediate is first reacted with 4-hydroxy-6-mercaptodibenzofuran. The free phenol is then acylated by 3—4 equiv of a symmetrical anhydride derived from an N -carbamate-blocked amino acid, in the presence of diisopropylethylamine in dichloromethane (ca. 10-30 min reaction time at 0 °C). 

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