124554-41-2Relevant academic research and scientific papers
Asymmetric desymmetrization of the diallyl acetals of alkynals by the enantioselective Pauson-Khand-type reaction catalysts
Dong, Eun Kim,Bo, Hyung Lee,Rajagopalasarma, Mudigonda,Genet, Jean-Pierre,Ratovelomanana-Vidal, Virginie,Jeong, Nakcheol
supporting information; experimental part, p. 2695 - 2700 (2009/10/14)
Asymmetric desymmetrization of the di-allyl acetals of alkynal (1) by an enantioselective Pauson-Khand-type reaction catalyst was studied. The corresponding 5-oxabicyclo[3.3.0]octenones (2) were obtained as a mixture of diastereomers (2a and 2b), which were hydrolyzed to afford a single enantiomer (3), in high yields (up to 88%) as well as excellent enantioselectivities (up to 97%).
A Pauson-Khand approach to new carbocyclic nucleoside analogs
Lanver, Andreas,Schmalz, Hans-Guenther
, p. 1444 - 1458 (2007/10/03)
The synthesis of three new carbocyclic nucleoside analogs (CNAs) with the nucleobase attached to a 3′-hydroxymethylcyclopent-2′-en-1′-yl scaffold is reported. A variety of symmetric dienynes (propargylic acetals of type 11) were used as substrates in a cobalt-mediated Pauson-Khand (PK) reaction to give bicyclic cyclopentenone derivatives of type rac-12 with high diastereoselectivity. These compounds are valuable building blocks for the synthesis of structurally diverse CNAs with a high biological potential as apoptosis-inducing agents. Starting from the PK product rac-12a, the synthesis of 4′-trialkylsilyloxyethyl-substituted nucleosides rac-18 and rac-19 (with 5-bromouracil and 6-chloropurine as a nucleobase, respectively) was accomplished in seven steps (28% and 37% overall yield). The regio- and diastereoselective nucleobase (NB) introduction was achieved by Pd 0-catalyzed allylic substitution. Starting from the PK product rac-12e, the 2′-phenyl-4′-trialkylsilyloxymethyl-substituted CNA rac-17 was prepared (6 steps, 29% yield)by exploitingan alternative protocol - a Mitsunobu reaction - for the NB introduction. The key intermediates 12a and 12e were obtained in virtually enantiopure form by kinetic resolution by means of oxazaborolidine-catalyzed borane reduction (CBS reduction) in the presence of a (R)-diphenylprolinol-derived B-methyl oxazaborolidine catalyst. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005.
SYNTHESIS AND CLAISEN REARRANGEMENT OF 1-ALLYLOXY-1-CARBOMETHOXY ALLENES
Sleeman, M. J.,Meehan, G. V.
, p. 3345 - 3348 (2007/10/02)
A number of allyl allenyl ethers(1) have been synthesised and shown to undergo the Claisen rearrangement.The kinetics of rearrangement of (1b) together with stereochemical data obtained, is consistent with a concerted mechanism for these rearrangements.
