已经描述了 β,γ-取代的烯丙基硼酸酯对醛的催化不对称加成。在 5 mol% 手性磷酸的促进下,该反应具有广泛的适用性、可扩展性和高效性,允许以高度对映和非对映选择性的方式形成带有相邻叔或季立体中心的 3,4-反/同-高烯丙醇(≤99% ee 和 dr >20:1)。涉及手性磷酸的刚性椅子状过渡态有助于高度控制的反应。
Chiral Phosphoramide-Catalyzed Enantioselective Addition of Allylic Trichlorosilanes to Aldehydes. Preparative Studies with Bidentate Phosphorus-Based Amides
作者:Scott E. Denmark、Jiping Fu、Michael J. Lawler
DOI:10.1021/jo052203h
日期:2006.2.1
that more than one Lewis basic moiety (phosphoramide) is involved in the rate- and stereochemistry-determining step of enantioselectiveallylation, bidentate chiral phosphoramides were developed. Different chiral phosphoramide moieties were connected by tethers of methylene chains of varying length. The rate and enantioselectivity of allylation with allyltrichlorosilane promoted by the bidentate phosphoramides
“High-surface alkali metals” can be conveniently prepared via deposition of corresponding metals on various supports such as sodium chloride, polyethylene, polypropylene and cross-linked polystyrene from their solutions in liquid ammonia. Alkali metals deposited on polymeric supports can be stored in form of stable suspensions in inert solvents and used for the acyloin and Dieckmann condensations and
Bi(cyclopentyl)diol-Derived Boronates in Highly Enantioselective Chiral Phosphoric Acid-Catalyzed Allylation, Propargylation, and Crotylation of Aldehydes
作者:Jinping Yuan、Pankaj Jain、Jon C. Antilla
DOI:10.1021/acs.joc.0c01646
日期:2020.10.16
catalytic addition of bi(cyclopentyl)diol-derived boronates to aldehydes promoted by chiralphosphoricacids, allowing for the formation of enantioenriched homoallylic, propargylic, and crotylic alcohols (up to >99% enantiomeric excess (ee), diastereomeric ratio (dr) >20:1). These boronate substrates provided superior enantioselectivities, allowing for the reactions to proceed with low catalyst loading
Nozaki−Hiyama−Kishi Reactions Catalytic in Chromium
作者:Alois Fürstner、Nongyuan Shi
DOI:10.1021/ja9625236
日期:1996.1.1
chromium-catalyzed additions of organic halides to aldehydes (“Nozaki−Hiyama−Kishi reactions”). The reactions are mediated by trimethylchlorosilane, and the active Cr2+ species is constantly recycled by means of nontoxic, commercial manganese powder as the stoichiometric reductant. This method nicely applies to different substituted aryl, heteroaryl, alkynyl, alkenyl, and allylhalides as well as to alkenyl triflates
We performed an organocatalyzed enantioselective kineticresolution (KR) of racemic diastereocontrolled secondaryalcohols bearing a quaternary stereocenter. This methodology is a general KR leading to the enantiocontrol of acyclic quaternary stereocenter with high levels of stereoselectivity (s up to 185) on a large scope. In addition, the hydroxyl function can easily serve as a traceless group by