Highly diastereoselective hydrosilylations of allylic alcohols
作者:Mark G. McLaughlin、Matthew J. Cook
DOI:10.1039/c4cc00138a
日期:——
The highly syn-selective hydrosilylation of allylic alcohols was developed which, following oxidation, provided 1,3 alcohols containing two contiguous stereocentres.
Asymmetric cross- and self-aldol reactions of aldehydes in water with a polystyrene-supported triazolylproline organocatalyst
作者:Patricia Llanes、Sonia Sayalero、Carles Rodríguez-Escrich、Miquel A. Pericàs
DOI:10.1039/c6gc00792a
日期:——
A polystyrene-immobilized triazolylproline has been prepared by a bottom-up approach involving co-polymerization with full regiocontrol. The resulting PS resin swells in water and has been applied to the enantioselective cross-aldol...
Dip in! A Rh/dippf catalyst generates aldehyde‐derived enol boranes at ambient temperature by isomerization of allyloxy‐ and homoallyloxyboranes. A one‐pot isomerization/cross‐aldol sequence provides aldehyde–aldehyde adducts in good yield with syn selectivity. Direct use of primary allylic and homoallylic alcohols was also achieved.
Rh-Catalyzed AldehydeAldehyde Cross-Aldol Reaction under Base-Free Conditions: In Situ Aldehyde-Derived Enolate Formation through Orthogonal Activation
The chemoselective generation of aldehyde‐derived enolates to realize an aldehydealdehyde cross‐aldol reaction is described. A combined Rh/dippf system efficiently promoted the isomerization/aldol sequence by using primary allylic, homoallylic, and bishomoallylic alcohols; secondary allylic and homoallylic alcohols; and trialkoxyboranes that were derivedfrom primary allylic and homoallylic alcohols
Confinement-Controlled, Either <i>syn</i>- or <i>anti</i>-Selective Catalytic Asymmetric Mukaiyama Aldolizations of Propionaldehyde Enolsilanes
作者:Tynchtyk Amatov、Nobuya Tsuji、Rajat Maji、Lucas Schreyer、Hui Zhou、Markus Leutzsch、Benjamin List
DOI:10.1021/jacs.1c07447
日期:2021.9.15
Protected aldols (i.e., true aldols derived from aldehydes) with either syn- or anti- stereochemistry are versatile intermediates in many oligopropionate syntheses. Traditional stereoselectiveapproaches to such aldols typically require several nonstrategic operations. Here we report two highly enantioselective and diastereoselective catalytic Mukaiyama aldol reactions of the TBS- or TES- enolsilanes
具有顺式或反式立体化学的受保护醛醇(即来自醛的真正醛醇)是许多低聚丙酸酯合成中的通用中间体。这种醛醇的传统立体选择性方法通常需要几个非战略性操作。在这里,我们报告了丙醛的 TBS-或 TES-烯醇硅烷与芳香醛的两种高度对映选择性和非对映选择性催化 Mukaiyama 羟醛反应。我们的反应以催化剂控制的方式直接提供有价值的甲硅烷基保护的丙醛醛醇,无论是合成还是反异构体。我们已经确定了一种特权 IDPi 催化剂基序,该基序专为控制这些醛醇化反应而设计,具有出色的选择性。我们展示了 IDPi 催化剂内核中的单原子修饰,用CF 2 H 基团替换 CF 3基团,如何导致醛的对映面分化发生戏剧性的转变。这种显着效果的起源归因于通过 CF 2 H 基团的非常规 C-H 氢键使催化腔变紧。