Felkin anh
Tīmeklis1999. gada 14. sept. · Three O -isopropylidene group-protected pentose aldehydes (methyl 2,3- O -isopropylidene-β- d - ribo -pentodialdo-1,4-furanoside ( 1 ), methyl 2,3- O -isopropylidene-α- d - lyxo -pentodialdo-1,4-furanoside ( 2 ), and 3- O -benzyl-1,2- O -isopropylidene-α- d - xylo -pentodialdo-1,4-furanose ( 3 )) were treated at −30 °C … Tīmeklis2024. gada 3. febr. · Anti-Felkin–Anh diastereoselectivity can be achieved for nucleophilic additions to α-chiral ketones upon stretching the ketone with a mechanical pulling force. Herein, a mechanochemical Felkin–Anh model is proposed for predicting the outcome of a nucleophilic addition to an α-chiral ketone. Essentially, the fully …
Felkin anh
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TīmeklisThe Felkin Anh T.S. provides a particularly useful model for predicting the stereochemical outcome of reactions involving carbonyl groups containing α-stereogenic centres. Providing the substituents at the α-centre are well differentiated in size, reaction through this T.S. can lead to products with excellent levels of stereocontrol. ...
TīmeklisThe Felkin-Anh Model [CP2, G5, M5, N2, N5, NNl, WHl, WH2, WP2, WTl] The attack of a hydride H on a prochiral carbonyl group can be accomplished either on the Re or Si face of the carbonyl, leading to a pair of diastereomers, as shown in the models in Figure 3.10. In these models L represents the most bulky group, P the most polar, … Tīmeklis2012. gada 22. aug. · Under control: The classical polar Felkin–Anh model has been applied for the first time to the analysis of diastereoselectivity in acylation reactions (see scheme). Computational studies demonstrate that stereoelectronic effects control the enantioselectivity in asymmetric catalytic alcoholysis of acyclic anhydrides.
Tīmeklis-, 视频播放量 1574、弹幕量 0、点赞数 33、投硬币枚数 28、收藏人数 44、转发人数 5, 视频作者 pxxyyz, 作者简介 pxxyyz.com，相关视频：Cram规则，Felkin-Anh规则，Cram螯合规则，苔藓虫素3片段合成，【有机化学001】克拉穆规则，cram规则2补充一下，羰基化合物详解12：安息香缩合Benzoin Condensation 终极练习 ... Tīmeklis现在Felkin-Anh规则已经成为解释和预测亲核试剂对α-手性醛酮加成的立体选择性的最常用规则。 规则特点： 1、R L 与羰基处于垂直交叉式。 2、亲核试剂从空间位阻更小的Rs一侧进攻。 3、亲核试剂从符合Burgi-Dunitz轨道角（107°）（点击查看详细介绍）的 …
Tīmeklis2024. gada 6. okt. · Cram's rule, proposed by Donald Cram in 1952, [1] was the earliest model proposed for rationalising the stereoselectivity of nucleophilic additions to carbonyl groups with α-stereocentres. The model involved assigning each α-substituent a relative "size" (small, medium, and large), then placing the carbonyl oxygen …
Tīmeklis2015. gada 2. nov. · One method to predict stereoinduction in asymmetric reactions is the Felkin-Anh model (derived from the more basic Cram model) that applies to nucleophile attacks on α-chiral … doug sahm flaco jimenezTīmeklis2007. gada 15. nov. · 1. Lược sử: Mô hình Felkin – Anh là một trong những mô hình tiến bộ khi xét một phản ứng có tính diastereoselectivity, nhưng lưu ý, trong thời điểm … racv magazine onlineTīmeklisFelkin is a surname. Notable people with the surname include: Hugh Felkin (1922–2001), research chemist. Robert William Felkin (1853–1926), medical … doug savant 1998TīmeklisAbout Press Copyright Contact us Creators Advertise Developers Terms Privacy Policy & Safety How YouTube works Test new features NFL Sunday Ticket Press Copyright ... doug savantTīmeklisFelkin-Anh is based on a reaction in which the metal and nucleophilic group both interact with the ends of the carbonyl bond simultaneously. They come together so that the … racv magazine 2022Tīmeklis2010. gada 8. aug. · Felkin-Anhモデルとは立体選択性が逆になるよう解釈される。すなわち、金属が配位性官能基Dおよびカルボニル酸素とキレートした配座が優先と … doug savant instagramTīmeklisThe Felkin-Anh conformation has the largest (and most electronegative in other cases) group perpendicular to the carbonyl. Attack on the Bürgi-Dunitz trajectory leads to the nucleophile, hydride in this case, passing close the substituents on the alpha carbon. The nucleophile, in this case, hydride, attacks from the least hindered approach. ... racv make a claim