4756-84-7Relevant academic research and scientific papers
The asymmetric synthesis of enantiopure C(5)-substituted transpentacins via diastereoselective conjugate additions to a β′-amino-α,β-unsaturated ester
Davies, Stephen G.,Fletcher, Ai M.,Roberts, Paul M.,Thomson, James E.,Zammit, Charlotte M.
, p. 208 - 221 (2020/01/31)
The asymmetric synthesis of a range of 1,2-anti-1,5-syn-transpentacins, bearing either alkyl, phenyl or hydroxymethyl substituents at the C(5)-position, has been achieved using the diastereoselective conjugate additions of Grignard reagents to an enantiopure β′-amino-α,β-unsaturated ester as the key step. In addition, the doubly diastereoselective conjugate addition of an enantiopure lithium amide reagent to the β′-amino-α,β-unsaturated ester provided access to the corresponding β,β′-diamino ester, which was subsequently converted to both (S,S)-(2,5-diaminocyclopent-1-yl)methanol and (S,S)-2,5-diaminocyclopentane-1-carboxylic acid. In each case, the final enantiopure products were obtained as single diastereoisomers (>99:1 dr) in good yields over five steps or fewer from commercially available starting materials.
Influence of functional substitution of allyl halides on their ni(co)4 promoted carbonylative cycloaddition with acetylenes
Camps, Francisco,Moreto, Josep M.,Pages, Lluis
, p. 3147 - 3162 (2007/10/02)
The effect of functional substitution of allyl halides on the outcome of the title reaction has been studied. Electron withdrawing and olefinic groups had different effects depending on their location. When they were placed at the central position of the allyl moiety carbonylative cycloaddition was found to be the main reaction, in acetone, to yield exclusively cyclohexenone (or aromatic) derivatives. In contrast, the same groups at the terminal site and in exteded conjugation with the allylic funtion were shown to favour competing side reactions such as allyl self-coupling. However, only cyclopentenones were obtained from either centrally or terminally substituted silylallyl halides. Substitution at both ends of the allyl moiety led to the formation of 4,5-disubstituted cyclopentenones. Important mechanistic information could be achieved from determination of the relative stereochemistry in these compounds.
