Process for the manufacture of gamma-acetoxytiglic aldehyde
申请人:Hoffman-La Roche Inc.
公开号:US05453547A1
公开(公告)日:1995-09-26
A novel process for the manufacture of .gamma.-acetoxytiglic aldehyde ("C.sub.5 -aldehyde"), which is known as an important starting material for the production of vitamin A acetate from a (.beta.-ionylidenethyl)triphenylphosphonium halide and C.sub.5 -aldehyde, comprises treating a pentenyn-3-ol of the formula HC.tbd.C--C(CH.sub.3)(OH)--CH.dbd.C(R).sub.2 (II), wherein both R's signify either hydrogen or methyl, with ozone, preferably in a lower alkanol R.sup.1 OH, wherein R.sup.1 signifies C.sub.1-4 -alkyl, to obtain an aldehyde 2-hydroxy-2-methyl-3-butynal of the formula HC.tbd.C--C(CH.sub.3)(OH)--CHO (III). The aldehyde III may be converted to the C.sub.5 -aldehyde by conventional means.
Diastereoselective Hydroxylation of <i>N</i>-<i>tert</i>-Butanesulfinyl Imines with 2-(Phenylsulfonyl)-3-phenyloxaziridine (Davis Oxaziridine)
作者:Anupam Karmakar、Po-Cheng Yu、Femil J. Shajan、Vijay K. Chatare、William A. Sabbers、Eduardo M. Sproviero、Rodrigo B. Andrade
DOI:10.1021/acs.orglett.2c02513
日期:2022.9.16
The diastereoselective α-hydroxylation of N-tert-butanesulfinyl metallodienenamine and metalloenamines with Davis oxaziridine affords α-hydroxy N-sulfinyl imines with 50–88% yield and up to 98:2 diastereomeric ratio. Dramatic changes in diastereoselectivity and stereoselectivity were observed by choice of metal bases. The mechanistic understanding for the switch in diastereoselectivity was assisted
N-叔丁烷亚磺酰基金属二烯胺和金属烯胺与 Davis oxaziridine的非对映选择性 α-羟基化得到 α-羟基N-亚磺酰基亚胺,产率为 50-88%,非对映体比例高达 98:2。通过选择金属碱可以观察到非对映选择性和立体选择性的显着变化。DFT 计算模型有助于对非对映选择性转换的机理理解,这表明面部方法受氮杂烯醇化物几何形状的控制。描述了 1,2-氨基醇不对称合成的一锅法。
Diversity-oriented synthesis of novel polycyclic scaffolds using polymer-bound reagents
A concise sequence utilizing a Petasis three component reaction followed by a tandem aza-Cope–Mannich cyclization afforded novel polycyclic heterocycles in good yield; alternative iminium cyclization based on a Pictet–Spengler reaction or aminal formation led to divergent pathways affording skeletal diversity.