220018-34-8Relevant academic research and scientific papers
Total synthesis of jerangolid D
Pospisil, Jiri,Marko, Istvan E.
, p. 3516 - 3517 (2008/01/01)
A short and convergent synthesis of jerangolid D is described. As key steps, a Blaise reaction is employed to construct the lactone ring, a diastereoselective multicomponent Sakurai condensation leads to the dihydropyran ring, and the skipped diene is ass
Total synthesis of rutamycin B, a macrolide antibiotic from Streptomyces aureofaciens
White,Hanselmann,Jackson,Porter,Ohba,Tiller,Wang
, p. 5217 - 5231 (2007/10/03)
Rutamycin B (2) was synthesized from three principal subunits, spiroketal 75, keto aldehyde 83, and aldehyde 108. First, triol 62 was assembled by Julia coupling of sulfone 56 with aldehyde 58 followed by an acid-catalyzed spiroketalization. The three hydroxyl functions of 62 were successfully differentiated, leading to phosphonate 75. The latter was condensed in a Wadsworth-Emmons reaction with 83, prepared in six steps from (R)-aldehyde 76, to give 92. Coupling of the titanium enolate of 92 with 108 afforded Felkin product 109 with high stereoselectivity in a process that is critically dependent on the presence of the p-methoxybenzyl ether in the aldehyde. Transformation of 109 via aldehyde 116 to vinylboronate 122 was followed by macrocyclization under Suzuki conditions to yield 123. Exhaustive desilylation of the latter yielded rutamycin B.
Approaches to a synthesis of galbonolide B
Smith, Peter M.,Thomas, Eric J.
, p. 3541 - 3556 (2007/10/03)
An approach to the C(7)-C(15) fragment of galbonolide B 2 has been completed in which the diene fragment 51 was assembled from (R)-3-tert-butyldimethylsilyloxypentan-2-one 29 by conversion into the unsaturated ester 30, acylation of the sulfone 47 using this ester, reductive desulfurisation, methylenation using a Wittig reaction and deprotection. Following model studies, the aldehyde 62, prepared by oxidation of the alcohol 51, was converted into a mixture of the epimeric alcohols 63 and these were converted into the di(methylene)tridecadienoic acid 65 using a phosphine catalysed Ireland-Claisen rearrangement. Sharpless epoxidations of the alcohol 67 using either L-(+)- or D-(-)-diethyl tartrate were highly stereoselective and gave the epoxides 68 and 69 which were clearly distinguishable. Model studies using the heptadiene monoepoxide 70 led to a synthesis of the monoprotected dihydroxy aldehyde 76 so establishing a protocol for the introduction into the vicinal diol of the galbonolides. Finally, aldol addition of tert-butyl acetate to the aldehyde 78 followed by selective protection, deprotection and cyclisation completed a synthesis of the macrolide 85.
