Zoanthenol, isolated from Zoanthus sp., possesses an extremely complex architecture including congested quaternary carbons. We describe a concise synthesis of the fully functionalized ABC-ring of zoanthenol based on sequential radical reactions.
The Important Role of the Byproduct Triphenylphosphine Oxide in the Magnesium(II)-Catalyzed Enantioselective Reaction of Hemiacetals and Phosphorus Ylides
作者:Linqing Wang、Dongxu Yang、Dan Li、Xihong Liu、Pengxin Wang、Kezhou Wang、Haiyong Zhu、Lutao Bai、Rui Wang
DOI:10.1002/anie.201804177
日期:2018.7.16
By employing a simple in situ generated magnesium catalyst, a direct asymmetric reaction between hemiacetals and phosphorusylides was achieved through a tandem Wittig–oxa‐Michael reaction sequence. Enantioenriched chromans, isochromans, and tetrahydropyrans were obtained in good chemical yields, and (−)‐erythrococcamide B was synthesized in enantioenriched form. The byproduct triphenylphosphine oxide
Process for producing aspartame derivatives, process for purifying aspartame derivatives, production intermediates, and process for producing production intermediates
申请人:AJINOMOTO CO., INC.
公开号:US20020127320A1
公开(公告)日:2002-09-12
N-[N-[3-(2-hydroxy-substituted phenyl)propyl]-L-&agr;-aspartyl]-L-phenylalanine 1-methyl ester derivatives, which are useful as sweeteners, may be conveniently produced by subjecting a 2-hydroxychroman derivative having various substituents on the benzene ring and aspartame to a reductive alkylation reaction. These compounds may be purified by subjecting such a derivative containing one or more impurities to a crystallization step to crystallize the same.
Further, there are provided a process for producing dialkoxychroman derivatives useful as intermediates for the production of such aspartame derivatives in the above process, and novel dialkoxychroman derivatives thus produced, which are excellent as the production intermediate.
PROCESSES FOR PRODUCING AND PURIFYING ASPARTAME DERIVATIVES AND PROCESS FOR PRODUCING PRODUCTION INTERMEDIATES
申请人:Ajinomoto Co., Inc.
公开号:EP1227104A1
公开(公告)日:2002-07-31
There are provided a process for producing an N-[N-[3-(2-hydroxy-substituted phenyl)propyl]-L-α-aspartyl]-L-phenylalanine 1-methyl ester derivative, which is useful as a sweetener, by subjecting a 2-hydroxychroman derivative having various substituents in a benzene ring and an aspartame to a reductive alkylation reaction, and a process for purifying the same by subjecting such derivative containing impurity(ies) to a crystallization step to crystallize the same.
Further, there are provided a process for producing a dialkoxychroman derivative useful as a production intermediate for the above aspartame derivative in the above process, and novel dialkoxychroman derivatives thus produced, and excellent as the production intermediate.
Brønsted Acid Catalyzed Intramolecular Allylic Substitution Reaction of Allylic Alcohols: A Facile Synthesis of 2-Vinylchromans
作者:Chang-Hua Ding、Bin Xu、Yun-Fan Li、Yu-Ting Xi、Kai-Ji Hu、Qitao Tan
DOI:10.1055/a-2301-9223
日期:——
Brønsted acidcatalyzedintramolecular allylic substitution reaction of secondary and tertiary allylic alcohols has been developed. A variety of 2-vinylchromans were efficiently prepared in moderate to excellent yields. The given method features wide substrate scope, operational simplicity, and mild, metal-free reaction conditions. The practicability of the method was demonstrated by a gram-scale reaction