https://commons.ru.ac.za/vital/access/manager/Index ${session.getAttribute("locale")} 5 Asymmetric induction in reactions of chiral carboxylic esters and silyl enol ethers https://commons.ru.ac.za/vital/access/manager/Repository/vital:4409 Wed 12 May 2021 19:42:31 SAST ]]> Camphor-derived chiral auxiliaries in asymmetric synthesis https://commons.ru.ac.za/vital/access/manager/Repository/vital:4417 99% d.e. for the bomane-2,3-diol acetals. In order to increase diastereofacial selectivity, a camphor-derived diol having a bulky substituent at C-10 was prepared, viz., phenyl 2,3-dihydroxybomane-10sulfonate, and α,β-unsaturated acetals of this diol were shown to undergo Simmons-Smith cyclopropanation with complete topological control (>99% d.e.), the diastereoselectivities being conveniently determined by ¹H and ¹³C NMR spectroscopy. Computer modelling, with the software package HYPERCHEM®, was used to explore the stereochemical aspects of the Simmons-Smith cyclopropanation, and hydrolysis of one of the cyclopropyl acetals has permitted the diastereoselective bias to be confirmed. (+)-Pinane-2,3-diol was also investigated as a chiral auxiliary in the Simmons-Smith reactions of α,β-unsaturated aldehydes, and moderate diastereoselectivities (20-30% d.e.) were observed. In a series of exploratory studies, the Diels-Alder reaction of the 2,3-dihydroxybomane-10-sulfonate acetal of trans-cinnamaldehyde with cyclopentadiene afforded a single cycloadduct, while OSO₄ dihydroxylation, MCPBA oxidation and alkylation of chiral acetals produced from both bomane-2,3-diol and phenyl 2,3-dihydroxybomane-10-sulfonate were less selective.]]> Wed 12 May 2021 18:04:19 SAST ]]> A synthetic and spectrometric study of the initial phases in urea-formaldehyde resin formation https://commons.ru.ac.za/vital/access/manager/Repository/vital:4383 Wed 12 May 2021 17:30:50 SAST ]]> Baylis-Hillman derived benzopyrans and related systems : a synthetic and mechanistic study https://commons.ru.ac.za/vital/access/manager/Repository/vital:4429 Wed 12 May 2021 16:36:44 SAST ]]>