Enzymatic acylation of cyclobutene and cyclobutane meso-diols at low temperature
摘要:
Acylation of cyclobutane and cyclobutene diols 5 and 8 in the presence of Pseudomonas fluorescens lipase below room temperature led to monoacetates (+)-6 and (-)-9, respectively. The chemical yields and enantiomeric excesses were nearly quantitative. (C) 2000 Elsevier Science Ltd All rights reserved.
Thermal electrocyclic ring-opening of cyclobutenes: stereoselective routes to functionalised conjugated (Z,E)- and (E,E)-2,4-dienals
作者:Falmai Binns、Roy Hayes、Stephen Ingham、Suthiweth T. Saengchantara、Ralph W. Turner、Timothy W. Wallace
DOI:10.1016/s0040-4020(01)89013-x
日期:——
The cyclobutenecarbaldehyde 12 undergoes thermal electrocyclic ring-opening at low temperature, producing the (2Z,4E)-hexadienal 13 exclusively. By contrast, unsymmetrical derivatives of cis-3-cyclobutene-1,2-dicarboxylic acid undergo ring-opening at 80–110°C with low levels of stereoselectivity, which vary according to the balance of the electronic and, to a lesser extent, the steric nature of the
The preparation and electrocyclic ring-opening of cyclobutenes: Stereocontrolled approaches to substituted conjugated dienes and trienes
作者:Falmai Binns、Roy Hayes、Kevin J. Hodgetts、Suthiweth T. Saengchantara、Timothy W. Wallace、Christopher J. Wallis
DOI:10.1016/0040-4020(96)00039-7
日期:1996.3
Thermal electrocyclic ring-opening of 4-alkyl-2-cyclobutene-1-carbaldehydes occurs at low temperature to give (2Z,4E)-alkadienals exclusively, and the process is exploited in transforming cis-3-cyclobutene-1,2-dimethanol 1 into a variety of naturally occurring 1,3,5-alkatrienes and 2,4-decadienoates. Desymmetrisation of 1 with Pseudomonas fluorescens lipase gives access to both enantiomers of 3-oxabicyclo[3
The addition of organometallic reagents to 3-oxabicyclo[3.2.0]hept-6-en-2-ol: A stereoselective route to 6-oxygenated (2Z,4E)-alkadienals
作者:Kevin J. Hodgetts、Christopher J. Wallis、Timothy W. Wallace
DOI:10.1016/s0040-4039(00)60752-9
日期:1994.6
The additions of various organometallic species to 3-oxabicyclo[3.2.0]hept-6-en-2-ol are diastereoselective; the results are consistent with addition to the less hindered face of a metal-chelated form of the corresponding γ-hydroxyaldehyde.
Preparation of highly enantiomerically enriched cyclobutane and cyclobutene diols
作者:Christophe Pichon、Christian Alexandre、François Huet
DOI:10.1016/j.tetasy.2004.02.018
日期:2004.4
Cyclobutene (+)-9, (+)-12, (+)-13, (+)-15, and cyclobutane (+)-19, (+)-22, (+)-23, (+)-25 diols were obtained in high enantiomeric excesses from monoacetates (−)-23 or (+)-16. An alternative method for obtaining (+)-22 and (+)-25 involved the resolution of cyclobutane 1,2-dicarboxylic acid.
An efficient synthesis of the 2-azabicyclo[2.1.1]hexane ring system has been accomplished starting from cis-cyclobut-3-ene-1,2-dicarboxylic anhydride 7, which was prepared using a photochemical method. The key step of this new strategy involved a stereoselective electrophilic addition of phenylselenyl bromide to the double bond of cyclobutene dicarbamate 16 derived from 7. The subsequent ring closure