Dynamic Induction of Optical Activity in Triarylmethanols and Their Carbocations
作者:Bartosz Stasiak、Agnieszka Czapik、Marcin Kwit
DOI:10.1021/acs.joc.0c02289
日期:2021.1.1
A series of artificial triarylmethanols has been synthesized and studied toward the possibility of exhibiting an induced optical activity. The observed chiroptical response of these compounds resulted from the chiral conformation of a triarylmethyl core. The chirality induction from a permanent chirality element to the liable triarylmethyl core proceeds as a cooperative and cascade process. The OH···O(R)
A mechanism for efficient proton-transfer catalysis. Intramolecular general acid catalysis of the hydrolysis of 1-arylethyl ethers of salicylic acid
作者:Sarah E Barber、Kathryn ES Dean、Anthony J Kirby
DOI:10.1139/v99-080
日期:1999.6.1
The tert-butyl (1) and 1-arylethyl ethers (2) of salicylic acid are hydrolyzed with efficient generalacid catalysis by the ortho-COOH group. The half-life of the neutral COOH form of the tert-butyl ether is 15.2 min at 39°, and the estimated acceleration by the COOH group of 2 ,X=M e, Y=Hi s 2.13 ◊1 0 5 . The salicylate leaving group from 2 (X = Me, Y = H) has an effective pKa of 2.9, compared with
Further Studies on the [1,2]-Wittig Rearrangement of 2-(2-Benzyloxy)aryloxazolines
作者:R. Alan Aitken、Andrew D. Harper、Ryan A. Inwood
DOI:10.3390/molecules27103186
日期:——
been examined. Significant limitations to the Wittig rearrangement of such systems are revealed. In terms of asymmetric Wittig rearrangement, good diastereoselectivity is obtained with a valine-derived 4-isopropyl oxazoline, but this is compromised by racemisation upon hydrolysis. More encouraging selectivity is achieved in the Wittig rearrangement of an acyclic phenylalanine-derived ortho-benzyloxy