Showing papers by "Philip L. Fuchs published in 2002"
TL;DR: A series of Taxol derivatives tethered at C2' and C-7 to glutamate and folate have been synthesized for evaluation as prodrugs which release Taxol via hydrolytic lability of their alpha-alkoxy and alpha-amino esters as mentioned in this paper.
123 citations
TL;DR: In this article, neutral dioxoperoxy chromium was shown to undergo C−H oxidation with retention of stereochemistry in the presence of an olefin without concomitant epoxidation.
Abstract: H5IO6 in the presence of catalytic chromoyl diacetate is a powerful method for oxidation of C−H bonds. Tertiary and oxygen activated C−H bonds are oxidized to tertiary alcohols or ketones at temperatures as low as −40 °C. The putative reagent is neutral dioxoperoxy chromium[VI] which undergoes C−H oxidation with retention of stereochemistry. This reagent appears to be the first reagent capable of oxidation of a C−H bond in the presence of an olefin without concomitant epoxidation.
91 citations
TL;DR: The structure of the North spiroketal moiety of ritterazine M has been corrected from 1a to 1b by comparison of published spectra of the natural product with five synthetic spiro ketal−alcohols.
40 citations
TL;DR: Two methods have been developed for the synthesis of epoxide 36 using (+)-pulegone 25 as an enantiopure starting material and an oxygen-directed alkylative oxidation reaction that re-establishes the dienyl sulfone functionality with concomitant 1,3-transposition of the sulfone moiety.
40 citations
TL;DR: The addition of carbon nucleophiles toSS-9a, SS-9b is high yielding and stereospecific, and the addition ofcarbon nucleophile to SS-8a,SS-8b is low yielding, but the combination of these two is effective in producing chiral synthetic equivalents of enones a and b.
Abstract: Enantiopure epoxyvinyl sulfones SS-9a, SS-9b, produced from Jacobsen epoxidation of 2-phenylsulfonyl 1,3-cyclohexa- and cycloheptadiene, are used as a template for the construction of substituted cycloalkenones and as chiral synthetic equivalents of enones a and b. The addition of carbon nucleophiles to SS-9a, SS-9b is high yielding and stereospecific. Enantiopure α,β- and γ-substituted cycloalkenones are easily constructed using a variety of methods.
39 citations
TL;DR: In this paper, a 16-operation process was used to convert hecogenin acetate to ritterazine M in 16 operations with an average yield per opearation of 87% and a linear yield of 12%.
37 citations
TL;DR: Oxidative functionalization (or removal) of a steroidal C18 methyl group is possible using a previously unknown dyotropic rearrangement of a seven-membered fused C-ring lactone to a 6-ring spiro lactone.
Abstract: Oxidative functionalization (or removal) of a steroidal C18 methyl group is possible using a previously unknown dyotropic rearrangement of a seven-membered fused C-ring lactone to a 6-ring spiro lactone. Spiroketal equilibration led to the 23-deoxy South analogue of cephalostatin 1 (1) in only 12 steps (23% overall yield) from hecogenin acetate 4, and to strained diene South 1 analogue 30 in 11 steps (28% overall). Total synthesis of 23‘-deoxy cephalostatin 1 (3) was accomplished in 16 operations from 4 (9% overall; average 86% yield per operation), and that of 16‘,17‘-dehydro-23‘-deoxy cephalostatin 1 (36) in 15 operations from 4 (8% overall; av 84%/op).
37 citations
TL;DR: A large-scale and inexpensive synthesis of dienes 1 and 2 has been developed via a four-step procedure starting with benzenethiol and the corresponding cyclic ketone.
Abstract: A large-scale and inexpensive synthesis of dienes 1 and 2 has been developed via a four-step procedure starting with benzenethiol and the corresponding cyclic ketone. No chromatography is required.
16 citations
TL;DR: Synthesis of these models was efficiently accomplished by reductive cleavage of the spiroketal and Sharpless asymmetric dihydroxylation of an isopentyl, methyl 1,1-disubstituted olefin, followed by Suarez iodine[III] oxidative spirocyclization of monoprotected 1 degree,3 degree 1,2 diols.
Abstract: The structure of the North spiroketal moiety of ritterazine M has been corrected from 1a to 1b. This was accomplished by comparison of published spectra of the natural product with five synthetic spiroketal-alcohols. Synthesis of these models was efficiently accomplished by reductive cleavage of the spiroketal and Sharpless asymmetric dihydroxylation of an isopentyl, methyl 1,1-disubstituted olefin, followed by Suarez iodine[III] oxidative spirocyclization of monoprotected 1 degree,3 degree 1,2 diols.
4 citations