A Novel Synthesis of Dimethyl 2-Oxoalkenylphosphonate from Pulegone Hydrogen Chloride Adduct
作者:Koichi Kojima、Shinichi Saito
DOI:10.1055/s-1992-26274
日期:——
The one-step synthesis of dimethyl 2-oxoalkenylphosphonates 2 from pulegone (p-menth-4(8)-en-3-one) hydrogen chloride adduct 4 and dimethyl lithioalkylphosphonates is described.
The first enantioselectivetotalsynthesis of (+)‐steenkrotin A has been achieved in 18 steps and 4.2 % overall yield. The key features of the strategy entail a Rh‐catalyzed O−H bond insertion followed by an intramolecular carbonyl‐ene reaction, two sequential SmI2‐mediated Ueno–Stork and ketyl–olefin cyclizations, and a cascade intramolecular aldol condensation/vinylogous retro‐aldol/aldol process
Sodium bis(2-methoxyethoxy)(1,1,1,3,3,3-hexafluoro-2-propoxy)aluminum hydride, a new stereoselective reducing agent in a carbacyclin synthesis
作者:Susumu Harashima、Osamu Oda、Shigeo Amemiya、Koichi Kojima
DOI:10.1016/s0040-4020(01)87084-8
日期:1991.1
A new reducing agent (2j) reduced the enone (4) to give 15(S)-allylic alcohol (5a) with excellent regio- and stereoselectivity through a five membered ring transition state. Stereoselecrivity of this reaction will be explained based on the LUMO of the enone moiety. The resulting (5a) was led to a carbacyclin.
Prostaglandin derivatives, their preparation and their therapeutic use
申请人:Sankyo Company Limited
公开号:EP0276124A2
公开(公告)日:1988-07-27
Prostaglandin derivatives having an oxo group at specified positions in the a side chain and having the formula (I):
(in which R1 - R6 represent hydrogen or various organic groups, m is 0 - 5 and n is 2 - 5) have a variety of physiological effects, notably a strong anti-ulcer activity accompanied by a limited ability to inhibit blood platelet aggregation. They may be prepared by the oxidation of a corresponding compound in which the oxo group in the cyclopentane ring, and optionally that in the a side chain, is replaced by a hydroxy group.
Stereocontrolled synthesis of low-molecular-weight ?-O-glycosides from products of decyclization of acylated oligosaccharide glycals
作者:A. G. Tolstikov、O. F. Prokopenko、L. V. Spirikhin、G. A. Tolstikov
DOI:10.1007/bf00864541
日期:1992.5
Low-molecular-weight beta-O-glycosides with aliphatic polyfunctional aglycones were synthesized by Horner-Emmons olefination of O-glycosylated alpha,beta-unsaturated aldehydes prepared by acid opening of the dihydropyran ring in totally acylated lactal, cellobial, and gentiobial.