Total Synthesis and Absolute Configuration of Macrocidin A, a Cyclophane Tetramic Acid Natural Product
作者:Tomohiro Yoshinari、Ken Ohmori、Marcus G. Schrems、Andreas Pfaltz、Keisuke Suzuki
DOI:10.1002/anie.200906362
日期:2010.1.25
iridium‐catalyzed asymmetric hydrogenation without fission of the CI bond, the macrolactam formation by intramolecular ketene trapping, and the Lacey–Dieckmann cyclization for the construction of the tetramic acid ring.
Toward the Development of a General Chiral Auxiliary. A Total Synthesis of (+)-Tetronolide via a Tandem Ketene-Trapping [4 + 2] Cycloaddition Strategy
作者:Robert K. Boeckman,、Pengcheng Shao、Stephen T. Wrobleski、Debra J. Boehmler、Geoffrey R. Heintzelman、Antonio. J. Barbosa
DOI:10.1021/ja0581346
日期:2006.8.1
A highly convergent, enantioselective totalsynthesis of the aglycone of the tetrocarcins, (+)-tetronolide, is described. The synthesis highlights the use of several new methods, including camphor auxiliary-directed asymmetric alkylation and the enantioselective preparation of acyclic mixed acetals bearing chirality at the acetal center, and the highly efficient connection of the two major precursors
Studies directed toward the total synthesis of tetronolide 1. An enantioselective synthesis of the octahydronaphthalene unit
作者:Robert K. Boeckman、Thomas E. Barta、Scott G. Nelson
DOI:10.1016/s0040-4039(00)79871-6
日期:1991.8
An efficient enantioselective route to the octahydronaphthalene unit present in tetronolide (1), the stereochemically complex aglycone common to the tetrocarcins, a novel group of antitumor substances, is described. The sequence employs the intramolecular Diels-Alder reaction to control the relative stereochemistry present on the trans decalin ring system, and incorporates a masked acylating agent
C-phosphorylation of enolates: an alternate route to complex carbonyl-activated phosphonates
作者:Robert K. Boeckman、Theodore M. Kamenecka、Scott G. Nelson、James R. Pruitt、Thomas E. Barta
DOI:10.1016/s0040-4039(00)78790-9
日期:1991.6
A one-pot two-step phosphorylation procedure is described which is suitable for the preparation of thermally lacible or highly substituted dialkyl phosphonates for use in Horner-Emmons olefinations. Such systems are not readily available using the traditional methods such as the Arbuzov reaction or acylation of dialkyl phosphonate carbanions. Reaction of dioxinone lithium enolates with diethyl chlorophosphite
Studies on the synthesis of kijanolide: synthesis of the 2-acyl spirotetronate and investigations concerning the coupling of the top and bottom half fragments
作者:William R. Roush、Bradley B. Brown
DOI:10.1021/jo00060a036
日期:1993.4
Several studies directed toward the synthesis of kijanolide are described. First, a method for synthesis of the 2-acyl spiro tetronate substructure (15,52) via a Dieckmann cyclization protocol was developed. Second, a 10-step synthesis of 7,7-dibromo-2,4-dimethyl-5-[(tert-butyldiphenylsilyl)oxy]heptenal 35 was developed, making possible the synthesis of a range of kijanolide bottom half precursors via olefination (e.g., 35 + 23 --> 38) and cross-coupling reactions (e.g., 38 --> 19). This solves the problems encountered due to the introduction of the C(7)-hydroxyl group in our previous synthesis of the kijanolide bottom half 2.2a Third, a highly efficient procedure was developed for the coupling of kijanolide top half 8 and dioxinone 38 via an acyl ketene intermediate. This is the most efficient of several methods examined for acylating the hindered tertiary hydroxyl group of 8. Attempts to perform the IMDA reaction of 46, 47 or 9 (R = SiEt3) generated in situ from coupling of 8 and the acyl ketene (20) derived from 42 were thwarted by the unexpected tendency of beta-keto esters like 47 to fragment and decarboxylate via the acyl ketene intermediate at temperatures above 115-degrees-C. 2-Acyl tetronates 53 and 54 were prepared, but these systems decomposed upon attempted IMDA cyclization at temperatures approaching 190-degrees-C.