Isolation of Intermediaryanti-Aldol Adducts of the Horner-Wadsworth-Emmons Reaction Utilizing Direct Titanium-Aldol Addition and Successive Brønsted Acid Promoted Stereoselective Elimination Leading to (Z)-α,β-Unsaturated Esters
Synergistic Relay Reactions To Achieve Redox‐Neutral α‐Alkylations of Olefinic Alcohols with Ruthenium(II) Catalysis
作者:Chen‐Chen Li、Jian Kan、Zihang Qiu、Jianbin Li、Leiyang Lv、Chao‐Jun Li
DOI:10.1002/anie.201915218
日期:2020.3.9
the first Grignard-type nucleophilic addition using olefinicalcohols as latent carbonyl groups, providing a higher yield of the corresponding secondary alcohol than the classical hydrazone addition to aldehydes does. A broad scope of unsaturated alcohols and hydrazones, including some complex structures, can be successfully employed in this reaction, which shows the versatility of this approach and
Six-membered N-Heterocyclic Carbene-based catalysts for asymmetric reactions
申请人:McQuade D. Tyler
公开号:US20110054170A1
公开(公告)日:2011-03-03
The present invention provides a catalyst complex or ligand, and compositions thereof, for use in a variety of organic reactions having high reactivity and enantioselectivity. The catalyst is a N-heterocyclic carbene having three fused rings with first and second rings being six-membered rings and the third being a five-membered ring. The first ring is fused to the second and has four substituents. The second ring has two nitrogens flanking a carbene atom with one nitrogen bound to a substituent. The carbene atom may optionally be bonded to a metal. The third ring is fused to the second ring and contains two nitrogens. The third ring of the catalyst has a double bond and two substituents on adjacent non-fused carbons. A non-fused nitrogen of the third ring is partially bonded to another substituent. Methods for the synthesis and use of the catalyst embodiments of the present invention are also provided.
A compound of formula [I-W]:
wherein each symbol is as defined in the description, or a pharmaceutically acceptable salt thereof.
翻译结果为:具有公式[I-W]的化合物:其中每个符号如描述中定义,或其药物可接受的盐。
Isolation of Intermediary<i>anti</i>-Aldol Adducts of the Horner-Wadsworth-Emmons Reaction Utilizing Direct Titanium-Aldol Addition and Successive Brønsted Acid Promoted Stereoselective Elimination Leading to (<i>Z</i>)-α,β-Unsaturated Esters
The reagent TiCl4-Et3N was used in the Horner-Wadsworth-Emmons (HWE)-type reaction of triethylphosphonocarboxylates with aldehydes, wherein unstable intermediary aldol adducts were isolated with anti-selectivity. Subsequent Brønsted acid promoted stereoselective elimination was successfully performed using TBS-benzamide-pyridinium triflate to give the less-accessible Z-α,β-unsaturated esters