Transformation of the cyclohexane ring to the cyclopentane fragment of biologically active compounds
- Natalya Akhmetdinova,
- Ilgiz Biktagirov and
- Liliya Kh. Faizullina
Beilstein J. Org. Chem. 2025, 21, 2416–2446, doi:10.3762/bjoc.21.185
Graphical Abstract
Scheme 1: Ozonolysis–cyclization sequence in the synthesis of echinopine A (3).
Scheme 2: Ozonolysis–cyclization sequence in the synthesis of taiwaniaquinoids 7–12.
Figure 1: Iridoid skeleton.
Scheme 3: Ozonolysis–cyclization sequence in the synthesis of compounds 17a,b, 18 and 19 with iridoid topolog...
Scheme 4: Oxidation–aldol condensation sequence in the synthesis of compounds 21 and 23 with iridoid topology....
Scheme 5: Oxidation–aldol condensation sequence in the synthesis of compounds 29 and 30 with iridoid topology....
Scheme 6: Method for ring contraction in the absence of a double bond in a six-membered ring of triterpenoids....
Scheme 7: Oxidation–Dieckmann cyclization sequence in the synthesis of a new nortriterpenoid 39.
Scheme 8: Oxidation–Dieckmann cyclization sequence in the synthesis of 18,19-di-nor-cholesterol (40).
Scheme 9: Oxidation–cyclization sequence in the synthesis of 3-ethyl-substituted betulinic acid derivatives 49...
Scheme 10: Benzilic acid-type rearrangement in the synthesis of 4β-acetoxyprobotryane-9β,15α-diol (52).
Scheme 11: Benzilic acid-type rearrangement in the synthesis of (−)-taiwaniaquinone H (11).
Scheme 12: Benzilic acid-type rearrangement in the synthesis of dactylicapnosines A (63) and B (64).
Scheme 13: Aza-benzilic acid-type rearrangement in the synthesis of (+)-stephadiamine (71).
Scheme 14: α-Ketol rearrangement in the synthesis of saffloneoside (73).
Scheme 15: Conversion of (−)-preaustinoid A (80) to (−)-preaustinoid B (81) via α-ketol rearrangement.
Scheme 16: α-Ketol rearrangement in the synthesis of 2,8-oxymethano-bridged diquinane 90.
Scheme 17: Oxidative ring contraction during the synthesis of (+)-cuparene (91) and (+)-tochuinylacetate (92).
Scheme 18: Semipinacol rearrangement in the synthesis of diterpenoids 97–100.
Scheme 19: Co-catalyzed homoallyl-type rearrangement in the syntheses of meroterpenes 106–109.
Scheme 20: Ring contraction reaction promoted by TTN·3H2O and HTIB in the synthesis of indanes.
Scheme 21: Rearrangement involving a hypervalent iodine compound in the synthesis of derivative 120.
Scheme 22: Wolff rearrangement in the synthesis of taiwaniaquinones A (7), F (8), taiwaniaquinols B (10), D (1...
Scheme 23: Wolff rearrangement in the synthesis of cheloviolene C (128), seconorrisolide B (129), and seconorr...
Scheme 24: Wolff rearrangement in the synthesis of (−)-pavidolide B (134).
Scheme 25: Wolff rearrangement in the synthesis of presilphiperfolan-8-ol (141).
Scheme 26: Photochemical rearrangement in the synthesis of cyclopentane derivatives 147a,b.
Scheme 27: Synthesis of cyclopentane derivatives 147a and 151.
Scheme 28: Photochemical rearrangement in the synthesis of cyclopentane derivative 153.
Scheme 29: Photochemical rearrangement in the synthesis of tricyclic ketones 155, 156.
Scheme 30: Photochemical rearrangement in the synthesis of cis/trans salts 160.
Figure 2: Scope of the photoinduced carboborative ring contraction of steroids. Reaction conditions: steroid ...
Scheme 31: Photoinduced carboborative ring contraction in the synthesis of artalbic acid (180).
Scheme 32: Synthetic versatility of the photoinduced carboborative ring contraction.
Scheme 33: Methods of disclosure of epoxide 189.
Scheme 34: Methods of disclosure of epoxide 190.
Scheme 35: Rearrangement of α,β-epoxy ketone 197.
Scheme 36: Acid-induced rearrangement in the synthesis of perhydrindane ketones 202 and 205.
Scheme 37: Rearrangement of epoxyketone 208 in the synthesis of huperzine Q (206).
Scheme 38: Rearrangement of epoxide 212 under the action of Grignard reagent.
Scheme 39: Semipinacol rearrangement of epoxide 220 in the synthesis of (−)-citrinadin A (217) and (+)-citrina...
Scheme 40: Semipinacol rearrangement of epoxide 225 in the synthesis of hamigeran G (223).
Scheme 41: Semipinacol rearrangement of epoxide 231 in the synthesis of (−)-spirochensilide A (228).
Scheme 42: Wagner–Meerwein rearrangement in the synthesis of compound 234 with iridoid topology.
Scheme 43: Wagner–Meerwein rearrangement in the synthesis of compound 238 with iridoid topology.
Scheme 44: Wagner–Meerwein rearrangement in the synthesis of compound 241 with iridoid topology.
Scheme 45: Wagner–Meerwein rearrangement in the synthesis of lupane derivatives 245, 246, 248, and 249.
Scheme 46: Wagner–Meerwein rearrangement in the synthesis of weisaconitine D (252) and cardiopetaline (255).
Scheme 47: Wagner–Meerwein rearrangement in the synthesis of cardiopetaline (255).
