A Practical Method for Oxazole Synthesis by Cycloisomerization of Propargyl Amides
摘要:
2,5-Disubstituted and 2,4,5-trisubstituted oxazol-5-yl carbonyl compounds were prepared in good yields by a mild SiO2-mediated cycloisomerization of propargyl amides.
Organozinc Reagents in DMSO Solvent: Remarkable Promotion of S<sub>N</sub>2′ Reaction for Allene Synthesis
作者:Koji Kobayashi、Hiroshi Naka、Andrew E. H. Wheatley、Yoshinori Kondo
DOI:10.1021/ol801249w
日期:2008.8.7
The S N2' reaction of propragyl mesylates with organozinc reagents was dramatically improved in DMSOsolvent, and the stereoselective conversion of chiral substrates was successfully achieved using LiCl-free diorganozinc without the loss of optical purity.
Synthesis of propargylic fluorides from allenylsilanes
作者:Laurence Carroll、M? Carmen Pacheco、Ludivine Garcia、V?ronique Gouverneur
DOI:10.1039/b610013a
日期:——
Allenylsilanes reacted at room temperature in acetonitrile with Selectfluor, an electrophilic fluorinating reagent, to give secondary propargylic fluorides in moderate to good yields; mechanistically, a side-product resulting from a 1,2-silyl shift testifies to the presence of a cationic intermediate.
Stereospecific anti SE2′ fluorination of allenylsilanes: synthesis of enantioenriched propargylic fluorides
作者:Laurence Carroll、Samantha McCullough、Tom Rees、Timothy D. W. Claridge、Véronique Gouverneur
DOI:10.1039/b803888k
日期:——
The electrophilic fluorodesilylation of enantioenriched allenylsilanes proceeds with efficient transfer of chirality. The silylationâfluorination of propargylic alcohols occurs with overall retention of stereochemistry, a result consistent with a stereospecific anti SE2â² mechanism for the fluorination step.
Electrophilic Fluorodesilylation of Allenylmethylsilanes: A Novel Entry to 2-Fluoro-1,3-dienes
作者:M Carmen Pacheco、Véronique Gouverneur
DOI:10.1021/ol047319z
日期:2005.3.1
Various fluorodienes were prepared by treatment of the corresponding allenylmethylsilanes with Selectfluor. This is the first route to these compounds not based on the use of a fluorinated building block. The reaction allows the preparation of 2-fluoro-1,3-dienes with several substitution patterns, including di- and trisubstituted compounds.
Spirodiepoxide-Based Cascades: Direct Access to Diverse Motifs
作者:Rojita Sharma、Madhuri Manpadi、Yue Zhang、Hiyun Kim、Novruz G. Ahkmedov、Lawrence J. Williams
DOI:10.1021/ol201101e
日期:2011.7.1
Allene epoxide formation/opening reaction sequences enabled direct access to diverse products. Described here are a single flask procedure for allene preparation and allene oxidation/derivatization reactions that give, among others, diendiol, diyndiol, alpha'-hydroxy-gamma-enone, dihydrofuranone, butenolide, and delta-lactone products.