22672-76-0Relevant academic research and scientific papers
Application of furanyl carbamate cycloadditions toward the synthesis of hexahydroindolinone alkaloids
Padwa,Brodney,Dimitroff,Liu,Wu
, p. 3119 - 3128 (2001)
A convenient synthesis of various substituted hexahydroindolinones has been achieved by an intramolecular Diels-Alder cycloaddition reaction (IMDAF) of furanyl carbamates bearing tethered alkenyl groups. The initially formed [4 + 2]-cycloadduct undergoes nitrogen-assisted ring opening followed by deprotonation of the resulting zwitterion to give the rearranged ketone. The stereochemical outcome of the IMDAF cycloaddition has the sidearm of the tethered alkenyl group oriented syn with respect to the oxygen bridge. A synthetic route to (±)-mesembrane and (±)-crinane was accomplished using this methodology. It was possible to carry out a stereoselective reduction of the initially formed hexahydroindolinone ring to produce the cis-3a-aryl-hydroindole skeleton. A related [4 + 2]-cycloaddition/rearrangement sequence was also used for a formal synthesis of the Chinese ornamental orchid (±)-dendrobine. The tricyclic alkaloid core was formed stereoselectivity from the thermolysis of N-[(2-methyl-2-cyclopentenyl)methyl]-N-(4-isopropyl-furan-2-yl)carbamic acid tert-butyl ester. Kende's advanced intermediate 33 was prepared in seven additional steps by standard transformations, thereby completing a formal synthesis of (±)-dendrobine.
Total Synthesis of (±)-Crinane from 6,6-Dibromobicyclo[3.1.0]hexane Using a 5- exo- trig Radical Cyclization Reaction to Assemble the C3a-Arylated Perhydroindole Substructure
Lan, Ping,Banwell, Martin G.,Willis, Anthony C.
, p. 8493 - 8498 (2018)
Crinane embodies the tetracyclic framework associated with some of the most common Amaryllidaceae alkaloids. It has now been prepared in 10 steps from 6,6-dibromobicyclo[3.1.0]hexane (2). The initial step involves the thermally induced electrocyclic ring opening of cyclopropane 3 and capture of the resulting π-allyl cation with benzylamine to give an allylic amine that is readily elaborated to the 3°-amine 10. This last compound was engaged in a 5-exo-trig free radical cyclization reaction to give the C3a-arylated perhydroindole 11. Compound 11 was then converted, over two steps, into (±)-crinane, the hydrochloride salt of which has been subjected to single-crystal X-ray analysis.
Catalytic deacylative alkylations (DaA) of enolcarbonates: Total synthesis of (±)-Crinane
Das, Mrinal K.,Yadav, Abhinay,Majumder, Satyajit,Bisai, Alakesh
, (2020/07/03)
An efficient Pd(0)-catalyzed deacylative allylation (DaA) of enolcarbonates (as pro-nucleophile) of cycloalkanones sharing acyl functionality at C2-position with readily available allylic alcohols (as pro-electrophiles) is disclosed under mild reaction conditions. A wide variety of cycloalkanones with an aromatic ring and allyl group at C-2 position (all-carbon quaternary center) are obtained in good to excellent yields (36 examples). The usefulness of this methodology has been shown by a total synthesis of Amaryllidaceae alkaloid, (±)-crinane from 2-aryl cyclohexanone in 5 steps.
Concise Total Syntheses of (±)-Joubertiamine, (±)- O -Methyljoubertiamine, (±)-3′-Methoxy-4′- O -methyljoubertiamine, (±)-Mesembrane, and (±)-Crinane
Das, Mrinal Kanti,De, Subhadip,Bisai, Alakesh
, p. 2093 - 2104 (2016/07/06)
A method to access cis-3a-aryloctahydroindole alkaloids has been developed through a key strategy involving Eschenmoser-Claisen rearrangement of allylalcohol. This approach gives us an opportunity to access the all-carbon quaternary center required for ci
Synthesis of crinane utilizing an allylic sulfoxide for the construction of a hydroindole ring: Via vinylogous C-N bond formation
Raghavan, Sadagopan,Ravi, Anil
, p. 10222 - 10229 (2016/11/17)
The synthesis of crinane is disclosed via intramolecular C-N bond formation by the displacement of an allylic sulfoxonium salt. The allylic sulfide precursor was synthesized by a ring-closing metathesis reaction. The quaternary carbon stereocenter was created by alkylation of a benzylic cyanide. The allyl sulfide 14 was prepared by adding vinylmagnesium bromide to an α-chlorosulfide.
Concise total syntheses of (±)-mesembrane and (±)-crinane
Das, Mrinal Kanti,De, Subhadip,Shubhashish,Bisai, Alakesh
supporting information, p. 3585 - 3588 (2015/03/30)
A straightforward and unified strategy to access Amaryllidaceae alkaloids comprising a cis-3a-aryloctahydroindole scaffold has been developed. The strategy features Eschenmoser-Claisen rearrangement of allylalcohol as a key step for the installation of al
A general and efficient strategy for 7-aryloctahydroindole and cis-3a-aryloctahydroindole alkaloids: Total syntheses of (±)-γ- lycorane and (±)-crinane
Gao, Shuanhu,Tu, Yong Qiang,Song, Zhenlei,Wang, Aixia,Fan, Xiaohui,Jiang, Yijun
, p. 6523 - 6525 (2007/10/03)
A general and efficient approach to both 7-aryloctahydroindole and cis-3a-aryloctahydroindole alkaloids has been developed. The key step involves Michael additions of the corresponding kinetics and thermodynamics lithium enolates of ketone 9 to the versat
A general efficient strategy for cis-3a-aryloctahydroindole alkaloids via stereocontrolled ZnBr2-catalyzed rearrangement of 2,3-aziridino alcohols
Song, Zhen Lei,Wang, Bao Min,Tu, Yong Qiang,Fan, Chun An,Zhang, Shu Yu
, p. 2319 - 2321 (2007/10/03)
(Matrix presented) A short and general approach to the cis-3a-aryloctahydroindole alkaloids has been developed on the basis of a key stereocontrolled ZnBr2-catalyzed rearrangement of 2,3-aziridino alcohols. Two representative members, (±)-crina
An efficient synthesis of (±)-crinane using an intramolecular azide-olefin cycloaddition
Schkeryantz, Jeffrey M.,Pearson, William H.
, p. 3107 - 3116 (2007/10/03)
Refluxing 3-(2-azidoethyl)-3-[3,4-(methylenedioxy)phenyl]cyclohex-1-ene (2) in toluene for 24 hours afforded 3a-[3,4-methylenedioxy)phenyl]-3,3a,4,5,6,7-hexahydro-2H-indole (12) in quantitative yield. This reaction proceeds by intramolecular 1,3-dipolar cycloaddition of the azide onto the alkene followed by loss of nitrogen from the triazoline intermediate to give an imine. Reduction of the imine 12 with sodium cyanoborohydride in acetic acid/THF gave (3aR*, 7aR*)-3a-[3,4-methylenedioxy)phenyl]-2,3,3a,4,5,6,7,7a-octahydroindol e (13). Warming 13 with Eschenmoser's salt provided (±)-crinane (1). The synthesis of (±)-crinane (1) from cyclohexenone was accomplished in 8 steps in 23% overall yield.
