Consequences of acid catalysis in concurrent ring opening and halogenation of spiroketals.
[formula: see text] Lewis and/or Bronsted acid additives permit ring opening and halogenation of spiroketals at substantially reduced temperatures to produce omega-iodo enol ethers in improved yield and purity, which can undergo further reaction in the presence of distal electrophilic centers to give new steroid skeletons.
LaCour
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TG
Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, USA. lacour@purdue.edu
Tong
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Z
Fuchs
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PL
D000143:Acids; D002384:Catalysis; D006219:Halogens; D013141:Spiro Compounds / Q000138:chemical synthesis*; D013256:Steroids / Q000138:chemical synthesis* / Q000737:chemistry
D000143:Acids; D006219:Halogens; D013141:Spiro Compounds; D013256:Steroids