Highly efficient synthesis of alka-1,3-dien-2-yltitanium compounds from alka-2,3-dienyl carbonates. A new, practical synthesis of 1,3-dienes and 2-iodo-1,3-dienes
摘要:
Treatment of carbonates of alka-2,3-dien-1-ols 2 with (eta(2)-propene)Ti(O-i-Pr)(2) (I) resulted in oxidative addition to afford 1,3-dien-2-yltitanium compounds 3, which react readily with electrophiles such as H+, I-2 and aldehydes. The reaction with H+ and I-2 proceeds highly regioselectively, thus providing an efficient and practical method for synthesis of 1,3-dienes and 2-iodo-1,3-dienes. Copyright (C) 1996 Elsevier Science Ltd.
Catalytic Asymmetric Allenylation of Malonates with the Generation of Central Chirality
作者:Qiankun Li、Chunling Fu、Shengming Ma
DOI:10.1002/anie.201204346
日期:2012.11.19
Water plays an important role in a palladium‐catalyzed allenylation of diethyl malonate with 2,3‐allenyl acetates to yield centrallychiral allenyl malonates bearing synthetically useful functional groups (see scheme). The products were formed with 92–96 % ee in the presence of a bulky, electron‐rich biphenyl ligand at room temperature.
PROCESS FOR PRODUCING ALDEHYDES OR KETONES BY OXIDIZING ALCOHOLS WITH OXYGEN
申请人:Ma Shengming
公开号:US20120220792A1
公开(公告)日:2012-08-30
Provided is a process for producing aldehydes or ketones by oxidizing alcohols with oxygen, which comprises oxidizing alcohols to aldehydes or ketones in an organic solvent at room temperature with oxygen or air as an oxidant, wherein ferric nitrate (Fe(NO3)3.9H2O), 2,2,6,6-tetramethylpiperidine N-oxyl (TEMPO) and an inorganic chloride are used as catalysts, the reaction time is 1-24 hours, and the molar ratio of said alcohols, 2,2,6,6-tetramethylpiperidine N-oxyl and the inorganic chloride is 100:1˜10:1˜10:1˜10. The present process has the advantages of high yield, mild reaction conditions, simple operation, convenient separation and purification, recoverable solvents, substrates used therefor being various and no pollution, and therefore it is adaptable to industrialization.
demonstrated a very generalmethod for the preparation of essentially any terminal 2,3-allenol from the corresponding alkynols, which may be easily available from propargylic alcohols by alkylation, or from terminal alkynes by deprotonation and 1,2-addition with aldehydes or ketones, and subsequent base-catalyzed triple-bond migration. We have demonstrated a very generalmethod for the preparation of essentially
A practical procedure of propargylation of aldehydes
作者:Papiya Ghosh、Angshuman Chattopadhyay
DOI:10.1016/j.tetlet.2012.07.021
日期:2012.9
An operationally simple procedure of propargylation of aldehydes in moist solvent (distilled THF) has been developed through direct addition of propargyl bromide to aldehyde substrates mediated with low valent iron or tin. The metals were spontaneously prepared in situ employing bimetal redox strategy. Using different aldehydes as substrates (3a–k) both these metal mediated reactions took place producing
Palladium-Catalyzed Silylation of 2,3-Allenols with Unactivated Disilanes: Access to 2-Silyl-1,3-butadienes and α-Silyl-β-hydroxy Vinylsilanes
作者:Guang-Li Xu、Zhong-Xia Wang
DOI:10.1021/acs.orglett.1c04141
日期:2022.1.21
Regioselective silylation of 2,3-allenols with disilanes was carried out under catalysis of Pd2dba3/P(o-MeOC6H4)3. In the presence of Cs2CO3, the reaction achieved 2-silyl-1,3-dienes. Reaction of 1-aryl-2,3-allenols gave the products with excellent Z/E selectivity and E-isomers as the major species. Reaction of α-alkylallenols or α-alkyl-α-aryl-allenols resulted in products with moderate Z/E selectivity
在 Pd 2 dba 3 /P( o -MeOC 6 H 4 ) 3的催化下,用乙硅烷对 2,3-丙二烯醇进行区域选择性甲硅烷基化。在Cs 2 CO 3存在下,反应得到2-甲硅烷基-1,3-二烯。1-aryl-2,3-allenols的反应得到具有优异Z / E选择性和E-异构体为主要种类的产物。α-烷基烯丙醇或 α-烷基-α-芳基烯丙醇的反应产生具有中等Z / E选择性和E-异构体也是主要的。在没有碱的情况下,该反应产生α-甲硅烷基-β-羟基乙烯基硅烷,其在用Cs 2 CO 3处理后转化为2-甲硅烷基-1,3-二烯。