One catalyst for two distinct reactions: sequential asymmetric hetero Diels–Alder reaction and diethylzinc addition
作者:Haifeng Du、Xue Zhang、Zheng Wang、Kuiling Ding
DOI:10.1016/j.tet.2005.08.007
日期:2005.10
addition to the benzaldehyde, affording the corresponding secondary alcohol with up to 94.5% ee under optimized conditions. On the basis of these facts, the integration of two distinct enantioselective reactions, HDA and diethylzincaddition reactions, has been realized in one-pot with the promotion of a single chiralzinc catalyst in a sequential manner. The impact of diimine additive on the catalytic system
Nonlinear relationship between the enantioselectivities for asymmetric reactions of monofunctional and bifunctional substrates. Synthesis of practically optically pure diols by the catalytic enantioselective diethylation of terephthalaldehyde
作者:Kenso Soai、Hiroshi Hori、Masato Kawahara
DOI:10.1039/c39920000106
日期:——
An equation is presented which shows a nonlinear relationship between the enantioselectivities for asymmetric reactions of bifunctional and monofunctional substrates; practically complete enantioselectivity (100% e.e.) was observed in the enantioselective diethylation of terephthalaldehyde with diethylzinc using N,N-di(n- butyl) norephedrine and (S)-diphenyl(1-methylpyrrolidin-2-yl) methanol as chiral catalysts.
Enantio- and diastereoselective titanium-TADDOLate catalyzed addition of diethyl and bis(3-buten-1-yl) zinc to aldehydes a full account with preparative details
作者:Dieter Seebach、Albert K. Beck、Beat Schmidt、Yan Ming Wang
DOI:10.1016/s0040-4020(01)89373-x
日期:1994.4
enantioselective addition of alkyl groups from organozinc reagents to aldehydes (19 examples). With 0.05 – 0.20 equiv. of the diisopropoxy-Ti-TADDOLate bearing four 2-naphthyl groups and 1.2 equiv. of Ti(OCHMe2)4 in toluene or ether solution the best results are obtained: ≥ 98 : 2 enantiomer ratios with all types of aldehydes tested (saturated, olefinic, and acetylenic aliphatic, aromatic, and heteroaromatic)