Trimethylsilyl iodide catalyzed spirocyclization of amines. Synthesis of perhydrohistrionicotoxin

Thirty-five years of synthetic studies directed towards the histrionicotoxin family of alkaloids

“…In 1983, the groups of Carruthers and Godleski simultaneously published syntheses of (±)-2-depentyl-pHTX 18 utilising very similar Michael addition methodology (Scheme 13). [20][21][22][23] The Carruthers group started with cyclohexenone 122 and treated it with the Grignard reagent derived from 4-chlorobutan-1-ol. After acidic workup the resulting hydroxyl function was protected to give tosylate 123.…”

Synthese eines neuen Thienospirans: 6,7‐Dihydro‐1′‐methyl‐spiro[benzo[b]thiophen‐4(5H),2′‐piperidin]

“…Das Zielprodukt 6 wurde entsprechend der im Formelschema 3 dargestellten mehrstufigen Sequenz zuganglich gemacht. 6,thiophen-4(jH)-on (7), clas in einer dreistufigen Synthese aus Thiophen erhalten wurde [9], ergab clurch Umsetzung mit Tosylniethylisocyanid (Tos-MIC) [lo] in Anlehnung an die von OLDENZIEL [11] beschriebene Methode das Nitril8.…”

“…W-NMR (CDCI,): 173,s (s, CO); 137,l (s, C-7a); 130,9 (5, C-Ra); 127,l (d, (2-3); 121,5 (d, C-2); 51,4 (9,CH,);41,4 (d,25,7 (t,(3)(4)(5)(6); 24,4 (t, C-7); 21,3 (t, C-G). 5,6,7-Tetrahydr0-4-(4-phenoxy but-l-yl)-4-benzo[b]thiophencarbonsiiuremethyle s t e r (11) 5,37 g (53,l mmol) Diisopropylamin (ca.…”

New strategies in the synthesis of carbocyclic natural products

“…We were able to regioselectively alkylate the enolate of (ga) formed by the use of fluoride ion as described by Kuwajima we hoped we could see similar selectivity with the 3-alkylfurans. We synthesized compounds (24) and (26) as shown and subjected them to our normal reaction conditions with 1-carvone. Only 1-carvone could ultimately be recovered with no trace of any addition product.…”