This paper describes the details of our synthetic studies on the marine steroidal alkaloids cortistatins A and J. The key features of our strategy include (i) an efficient Knoevenagel/electrocyclic strategy to couple the diketone and the CD-ring fragment, (ii) a chemoselective radical cyclization to construct the oxabicyclo[3.2.1]octene B-ring system, (iii) a highly stereocontrolled installation of the isoquinoline unit, and (iv) a late-stage functionalization of the A-ring.
A stereoselective synthesis of des-A-ring steroids and has been achieved by an intramolecular cycloaddition of 3-isopropenyl-5-(4-methoxybenzocyclobutenyl) pentan-2-one-2-ethylene ketal and 1-(4-methoxy-benzocyclobutenyl)-4-methylpent-4-en-3-ol , respectively.
An efficient, stereoselective method for the construction of --4,5-(4′-oxo-1′,2′,3′,4′-tetrahydrobenzo)hydrindane — a possible intermediate to estradiol and cortisone
--1β-Hydroxy-8β-methyl-4,5-(4′-oxo-1′2′,3′,4′-tetrahydrobenzo)-hydrindane, a possibleintermediate to estradiol and cortisone, was synthesised stereoselectively by a thermolysis of benzocyclobutene as the key reaction.
Optically active trans-benzoperhydroindan 1 and its enantiomer have been synthesised by thermolysis of the optically active alkenic benzocyclobutene 10 as a key process.
Reappraisal of the diastereoselectivity of intramolecular Diels–Alder reactions of some o-quinodimethanes generated by benzocyclobutene thermolysis: some complementary results and an improvement
作者:Marc Port、Robert Lett
DOI:10.1016/j.tetlet.2006.04.128
日期:2006.7
In a synthetic approach to 19-nor steroids and in order to compare the diastereoselectivities observed for the intramolecular Diels–Alder reactions of o-quinodimethanes generated either from 1 or 2, the thermolysis of benzocyclobutenes such as 2 was reexamined. The IMDA diastereoselectivity was highly dependent on the nature of the protective group of the hydroxyl substituent at the unique chiral stereocentre
Stereospecific Syntheses of trans-1β-Hydroxy-8-methyl-4,5-(4'-methoxybenzo)-hydrindane, trans-1β-Hydroxy-8-methyl-4,5-(3'-methyl-4'-methoxybenzo)- hydrindane and d,l-Equilenin Methyl Ether
作者:D. K. Banerjee、S. Chatterjee、C. N. Pillai、M. V. Bhatt