The Asymmetric Synthesis of Amines via Nickel-Catalyzed Enantioconvergent Substitution Reactions
作者:Ze-Peng Yang、Dylan J. Freas、Gregory C. Fu
DOI:10.1021/jacs.0c13034
日期:2021.2.24
dialkyl carbinamines do not provide general access to amines wherein the two alkyl groups are of similar size (e.g., CH2R versus CH2R1). Herein, we report two mild methods for the catalytic enantioconvergent synthesis of protected dialkyl carbinamines, both of which use a chiral nickel catalyst to couple an alkylzinc reagent (1.1–1.2 equiv) with a racemic partner, specifically, an α-phthalimido alkyl chloride
手性二烷基卡宾胺在有机化学、药物化学和生物化学等领域具有重要意义,例如用作生物活性分子、手性配体和手性催化剂。不幸的是,大多数用于合成二烷基卡宾胺的催化不对称方法不提供获得其中两个烷基具有相似大小的胺的一般途径(例如,CH 2 R与CH 2 R 1 )。在此,我们报道了两种催化对映异构合成受保护的二烷基卡宾胺的温和方法,这两种方法都使用手性镍催化剂将烷基锌试剂(1.1-1.2当量)与外消旋伙伴偶联,特别是α-邻苯二甲酰亚氨基烷基氯或受保护的 α-氨基酸的N-羟基邻苯二甲酰亚胺 (NHP) 酯。该方法用途广泛,可提供带有一系列官能团的二烷基卡宾胺衍生物。对于NHP酯的偶联,我们进一步描述了一种一锅变体,其中NHP酯原位生成,允许从市售氨基酸衍生物一步生成对映体富集的受保护的二烷基卡宾胺;我们通过将其应用于一系列有趣的目标分子的有效催化对映选择性合成来证明该方法的实用性。
HERBICIDAL AND FUNGICIDAL 5-OXY-SUBSTITUTED 3-PHENYLISOXAZOLINE-5-CARBOXAMIDES AND 5-OXY-SUBSTITUTED 3-PHENYLISOXAZOLINE-5-THIOAMIDES
申请人:BAYER CROPSCIENCE AG
公开号:US20150245616A1
公开(公告)日:2015-09-03
Herbicidally and fungicidally active 5-oxy-substituted 3-phenylisoxazoline-5-carboxamides and 5-oxy-substituted 3-phenylisoxazoline-5-thioamides of the formula (I) are described.
In this formula (I), X, X
2
to X
6
, R
1
to R
4
are radicals such as hydrogen, halogen and organic radicals such as substituted alkyl. A is a bond or a divalent unit. Y is a chalcogen.
Efficient acetalisation of aldehydes catalyzed by titanium tetrachloride in a basic medium
作者:Angelo Clerici、Nadia Pastori、Ombretta Porta
DOI:10.1016/s0040-4020(98)00982-x
日期:1998.12
The acetalisation of aliphatic and aromatic aldehydes is achieved in a basic medium by using catalytic amount of Ti(IV) chloride in MeOH in the presence of NH3 or Et3N. The present protocol shows many advantages over the well known base or acid catalysis: in fact, in contrast to base-promoted acetalisation, aldehydes with electron-rich carbonyl groups react easily, enolizable aldehydes do not undergo
Regiospecific allylation of acetals with allylsilanes catalyzed by iodotrimethylsilane. Synthesis of homoallylethers
作者:Hideki Sakurai、Koshi Sasaki、Akira Hosomi
DOI:10.1016/0040-4039(81)80140-2
日期:1981.1
Allylation of acetals with allylsilanes is catalyzed by iodotrimethylsilane to give the corresponding homoallyl ethers, with regiospecific transposition of the allyl group.
缩醛与烯丙基硅烷的烯丙基化通过碘代三甲基硅烷催化,得到相应的均烯丙基醚,且烯丙基的区域特异性易位。
Thermochemical studies of carbonyl reactions. 2. Steric effects in acetal and ketal hydrolysis
作者:Kenneth B. Wiberg、Robert R. Squires
DOI:10.1021/ja00405a030
日期:1981.7
series of alkyl-substituted dimethyl acetals is reported. These data are critially compared with the enthalpies of hydrolysis from an analogous set of aliphatic dimethyl ketals derived from 2-alkanones. The acetals exhibit a significantly attenuated range in their enthalpies of hydrolysis relative to that for ketal hydrolysis. The free energies of acetalformation in solution were modeled by measurements