133467-37-5Relevant articles and documents
Total Synthesis of Nannocystin Ax
Poock, Caroline,Kalesse, Markus
, p. 4536 - 4539 (2017)
The total synthesis of nannocystin Ax in an overall yield of 11% with 14 steps as the longest linear sequence is reported. Nannocystin Ax is a cytotoxic 21-membered depsipeptide and was isolated from the myxobacterial genus Nannocystis sp. The synthesis u
An air stable moisture resistant titanium triflate complex as a lewis acid catalyst for C-C bond forming reactions
Bull, Steven D.,Davidson, Matthew G.,Johnson, Andrew L.,Mahon, Mary F.,Robinson, Diane E. J. E.
experimental part, p. 612 - 620 (2010/08/05)
An air and moisture stable C3-symmetric titanium(IV) triflate, supported by a tripodal amine-(tris-phenolate) ligand, has been synthesized and characterized by X-ray crystallography and shown to be a good Lewis acid catalyst for a range of aza-Diels-Alder, Diels-Alder, syn aldol, allylation, and alkylation reactions.
An Activated Germanium Metal-Promoted, Highly Diastereoselective Reformatsky Reaction
Kagoshima, Hirotaka,Hashimoto, Yukihiko,Oguro, Dai,Saigo, Kazuhiko
, p. 691 - 697 (2007/10/03)
Activated germanium metal, prepared by the reduction of germanium(II) iodide with potassium metal, was found to promote the Reformatsky reaction effectively under mild conditions. In the presence of activated germanium metal, the reactions of α-bromo ketones 2a and 2b and α-bromo imides 2e and 2f with benzaldehyde (1a) proceeded smoothly to give the corresponding β-hydroxy carbonyl compounds 3a, 3b, 3e and 3f, respectively, in good yields and with good syn diastereo- selectivity. The activated germanium metal-promoted, asymmetric Reformatsky reaction of enantiomerically pure-oxazolidinone derivatives 2g-j with various aldehydes 1a-d was also examined; the highest diastereoselectivity was achieved when (1S,2R)-2-amino-1,2-diphenylethanol- derived 2j was used as the Reformatsky donor. The excellent diastereoselectivity could be explained in terms of the formation of a chairlike, six-membered transition state between the aldehyde and enolate as in the Zimmerman-Traxler model. A single recrystallization of the Reformatsky adducts, followed by hydrolysis and subsequent esterification, led to enantiomerically pure methyl 3-hydroxy- 2-methylalkanoates 10j-m, with almost quantitative recovery of the enantiomerically pure 2-oxazolidinone 14.
