Studies were carried out to determine the absolute stereochemistry of
botryococcene (1). The natural product was degraded to two sets of 'y- and 8-
valerolactones. All enantiomeric variations of these lactones were synthesized in
optically pure form starting from (S)- and (R)-methyloxiranes. 1H NMR correlation of
natural and synthetic materials...
A synthetic approach toward the two major fragments of cathedulin K-19,
euonyminol (4) and dimethyl cathate (69), was investigated. Synthesis of
dimethyl cathate was accomplished in 3 steps starting from 73. Efforts directed
towards the synthesis of euonyminol, a highly oxygenated dihydroagarofuran
sesquiterpene, was advanced to a stage in which...
Several approaches to the synthesis of methymycin were
investigated. Segment A (39), containing functionality corresponding
to C-9, 10, and 11 of methynolide was made in
six steps from propionaldehyde in an overall yield of 37%.
Oxidation of 34 with silver nitrate gave 35 which, upon hydroxylation
with hydrogen peroxide, gave...
Several approaches to the synthesis of penicillin from 2-iminothioazolidine
50, from 2-thiothiazolidine 66 and by photocyclization of
77 and 78 were investigated. 2-Iminothiazolidine 50 was prepared
from dibromoester 45 by the action of benzylamine followed by treatment
of aziridine 46 with potassium or ammonium thiocyanate. Attempted
introduction of a two-carbon...
An approach to the generation of polyketides was investigated,
which involved ozonolysis of 6, 7 cyclopenteno -1> 4, 5, 8 -tetrahydromethoxy-
3-methylnaphthalene (26), to produce what is believed to be
polyketide 27. Compound 26 was formed by the following sequence:
Die ls -Alder addition of 1, 2 -dim.ethylenecyclopentane and 2...
A formal total synthesis of the macrolactone pyrolizidine alkaloid (-)-integerrimine (2), from R-(+)-citronellal (93) is described. Aldehyde 93 was converted to exo methylene derivative 94 which was reduced to allylic alcohol 95. The epoxides 96 and 98, obtained in a ratio of 3:1 respectively by Sharp less epoxidation of 95...
Verrucarol is the sesquiterpene portion of a number of macrocyclic di- and triesters of potential medicinal importance. In this study, a novel approach to the synthesis of this fungal metabolite is presented. An A-B-C route was investigated in which C-3 and C-4 of the C-ring were emplaced using a [2+2]...
The mycosporins, formerly called P310's are secondary metabolites
of fungi closely associated with fungal reproductive processes that
require light. The structurally related iminomycosporins are found in
marine plants and animals and may also have functions related to
light. In this study, approaches toward the asymmetric synthesis of
the mycosporins are...