in the copper-catalysed allylicsubstitution reaction of cinnamyl (=3-phenylprop-2-enyl) phosphate 12 with diethylzinc as a nucleophile. Ligands 5ae, 6ae, 8ae, and 11ae gave excellent ratios (100 : 0) of the SN2′/SN2 products (Scheme 6 and Table 1). Ligand 11ce, identified from the screening of a small library of ligands of general formula 11, promoted the allylicsubstitution reaction with moderate
Combinatorial Chemistry for Ligand Development in Catalysis: Synthesis and Catalysis Screening of Peptidosulfonamide Tweezers on the Solid Phase
作者:Arwin J. Brouwer、Heiko J. van der Linden、Rob M. J. Liskamp
DOI:10.1021/jo991628z
日期:2000.3.1
16a-e) was synthesized on the solid phase. This library was screened in a simultaneous substrate screening procedure for the ability to enantioselectively catalyze the Ti(O-i-Pr)(4)-mediated addition of diethylzinc to aldehydes. One of the best solid-phase tweezer catalyst (i.e., 16d, giving an ee of 32% in solid-phase catalysis) was resynthesized in solution (compounds 20 and 21). The now homogeneous solution-phase
Chiralβ-sulfonopeptides were synthesized both in solution and in the solidphase using the sulfonyl chlorides derived from enantiomerically pure 2-substituted taurines undermild coupling conditions [cat. 4-dimethylaminopyridine (DMAP) and excess methyl trimethylsilyl dimethylketene acetal (MTDA) as a proton trap].