Stereoselective acyclic synthesis via allylmetals: Threo vicinal diols from both - and -[gamma]-alkoxyallyltins and aldehydes

Both - and -[gamma]-alkoxyallyltins stereoselectively add to aldehydes in the presence of BF3[middle dot]OEt2 at -78[deg]C in CH2Cl2 to produce the threo (or syn) vicinal diol monoalkyl ether unit.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/26896/1/0000462.pd

Axial selectivity of 1,2-nucleophilic additions to 2-(Alkylidene)cyclohexanones: Is it higher than that of 2-cyclohexenones?

2-(Alkylidene)cyclohexanones embedded in steroid systems underwent 1,2-addition of both small and sterically demanding nucleophiles to yield exclusively the axial adducts, supporting the suggestion that 2-(alkylidene)cyclohexanones appear to have intrinsically higher axial selectivity than 2-cyclohexenones.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/30835/1/0000497.pd

On the factors that affect the mode of cyclization of [alpha]-silyl radicals: A method for angular hydroxymethylation by the 5-exo cyclization

The steric and stereochemical factors which favor the 5-exo cyclization of a 5-substituted 2-sila-5-hexen-1-yl radical have been probed. This radical cyclization approach constitutes a highly efficient and convenient means for the stereospecfic introduction of an angular hydroxymethyl group.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/29782/1/0000121.pd

Biosynthesis of Pregnenolone from Cholesterol by Mitochondrial Enzymes of Bovine Adrenal Cortex

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66357/1/j.1432-1033.1978.tb20931.x.pd

Synthesis of (+/-)-desepoxy-4,5-didehydromethylenomycin A

An efficient and regiochemically controlled synthesis of (+/-)-desepoxy-4,5-didehydromethylenomycin A is reported.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/24486/1/0000762.pd

(1E,3E)-4-acetoxy-1-phenyldimethylsilyl-1,3-butadiene as a surrogate for (1E,3E)-1,4- diacetoxy-1,3-butadiene: a highly efficient synthesis of (+/-)-shikimic acid

The 5-step synthesis of (+/-)-shikimic acid has been achieved in 55% overall yield from (1E,3E)-4-acetoxy-1-phenyldimethylsilyl-1,3-butadiene, starting with its Diels-Alder reaction with 2-(trimethylsilyl)ethyl acrylate and featuring the use of Fleming's one-pot procedure for the conversion of the phenyldimethylsilyl group to the hydroxyl as the salient, pivotal step in the synthesis.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/28968/1/0000805.pd

Mutagenicity in Salmonella assays of cyclohexane epoxide derivatives

15 Cyclohexane epoxide derivatives were synthesized and compared for direct mutagenicity an bacterial toxicity using Salmonella typhimurium strain TA100 in the liquid suspension and spot-test version of the Ames procedure. While no general correlations could be established for position and stereochemistry of the hydroxylated derivatives, an increase in mutagenicity was noted for the presence of electron-withdrawing groups and unsaturation in conjugation with the oxirane groups.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/25651/1/0000203.pd

Non-biomimetic route to deoxyadenosine adducts of carcinogenic polycyclic aromatic hydrocarbons

Aminotriols are prepared by direct aminolysis of the diol epoxides of polycyclic aromatic hydrocarbons, providing a substantial improvement over literature methods. The condensation of aminotriols with 6-halopurine deoxyribonucleosides provides a regio- and stereospecific synthesis of deoxyadenosine N6 adducts.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/29083/1/0000118.pd

A highly efficient synthesis of 3-methylcholanthrene

A five-step synthesis of 3-methylcholanthrene (1) has been achieved starting from 5-methylhomophthalic anhydride and N,N-diethyl-1-naphthamide in 55% over all yield. Treatment of a solution of the preformed lithium enolate of 5-methylhomophthalic anhydride (3) with an equimolar solution of 2-lithio-1-naphthamide (4), followed by acid hydrolysis, provides cleanly the spirobislactone 5 in 80% overall yield. In addition, the synthesis features a unique, highly selective double Friedel-Crafts cyclization of the aryl diacid 2 with PPA to give rise, after acetylation, to keto acetate 6