TY - JOUR
T1 - Hydroxylation of α, β-Unsaturated Nitriles and Esters in Steroid Systems
AU - Freerksen, Robert W.
AU - Raggio, Michael L.
AU - Thoms, Carrie A.
AU - Watt, David S.
PY - 1979
Y1 - 1979
N2 - The hydroxylation of α, β-unsaturated nitriles or α, β-unsaturated esters in various steroid systems using stoichiometric amounts of osmium tetroxide furnished -hydroxy ketones/aldehydes and α, β-dihydroxy esters in moderate yield. The absence of a C-21 acetoxy group in 17(20)-pregnene-20-carbonitriles or 5, 17(20)-pregnadiene-20-carbonitriles precluded using potassium permanganate to introduce the 17α-hydroxy 20-ketone synthon. However, the stoichiometric osmium tetroxide oxidation of various 17(20)-pregnene-20-carbonitriles furnished the 17α-hydroxy 20-ketones in moderate yield. α, β-Unsaturated nitriles derived from 3-ketones and 20-ketones were also hydroxylated to give α-hydroxy ketones and aldehydes in moderate yield. No regioselectivity for the Δ17, 20-double bond in 5, 17(20)-pregnadiene-20-carbonitriles was observed using osmium tetroxide. A catalytic osmium tetroxide-potassium chlorate oxidation of 17(20)-pregnene-20-carbonitriles required zinc nitrate to sequester cyanide ion liberated in the course of the hydroxylation. A brief investigation of osmium tetroxide oxidation of 5, 17(20)-pregnadienes bearing withdrawing groups at C-20 other than the nitrile disclosed an interesting hydroxylation of a 17(20)-unsaturated ester in the presence of a nonconjugated Δ5-double bond.
AB - The hydroxylation of α, β-unsaturated nitriles or α, β-unsaturated esters in various steroid systems using stoichiometric amounts of osmium tetroxide furnished -hydroxy ketones/aldehydes and α, β-dihydroxy esters in moderate yield. The absence of a C-21 acetoxy group in 17(20)-pregnene-20-carbonitriles or 5, 17(20)-pregnadiene-20-carbonitriles precluded using potassium permanganate to introduce the 17α-hydroxy 20-ketone synthon. However, the stoichiometric osmium tetroxide oxidation of various 17(20)-pregnene-20-carbonitriles furnished the 17α-hydroxy 20-ketones in moderate yield. α, β-Unsaturated nitriles derived from 3-ketones and 20-ketones were also hydroxylated to give α-hydroxy ketones and aldehydes in moderate yield. No regioselectivity for the Δ17, 20-double bond in 5, 17(20)-pregnadiene-20-carbonitriles was observed using osmium tetroxide. A catalytic osmium tetroxide-potassium chlorate oxidation of 17(20)-pregnene-20-carbonitriles required zinc nitrate to sequester cyanide ion liberated in the course of the hydroxylation. A brief investigation of osmium tetroxide oxidation of 5, 17(20)-pregnadienes bearing withdrawing groups at C-20 other than the nitrile disclosed an interesting hydroxylation of a 17(20)-unsaturated ester in the presence of a nonconjugated Δ5-double bond.
UR - http://www.scopus.com/inward/record.url?scp=0018346314&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0018346314&partnerID=8YFLogxK
U2 - 10.1021/jo01319a009
DO - 10.1021/jo01319a009
M3 - Article
AN - SCOPUS:0018346314
SN - 0022-3263
VL - 44
SP - 702
EP - 710
JO - Journal of Organic Chemistry
JF - Journal of Organic Chemistry
IS - 5
ER -