Indanones 426 Subject

Michael additions of C-nudeophiles such as the indanone 1 have been the subject of numerous further studies For example, the reaction between the indanone 1 and methyl vinyl ketone was effected by a solid-phase-bound quinine derivative in 85% yield and with remarkable 87% ee by d Angelo, Cave et al. [5], Co-polymers of cinchona alkaloids with acrylonitrile effected the same transformation Kobaya-shi and Iwai [6a] achieved 92% yield and 42% ee and Oda et al. [6b] achieved almost quantitative yield and up to 65% ee. Similarly, partially resolved 2-(hydroxy-methyl)quinudidine was found to catalyze the reaction between 1 and acrolein and a-isopropyl acrolein with induction of asymmetry, but no enantiomeric excesses were determined [7]. As shown in Scheme 4.4, the indanone 7 could be added to MVK with up to 80% ee under phase-transfer conditions, by use of the Cinchona-derived PT-catalysts 9a and 9b, affording the Michael-product 8 or enf-8, respectively [8]. The adducts 8 or ent-8 were intermediates in the stereoselective Robinson anellation of a cydohexenone ring to the indanone 7 [8],... 

The oxime nitrogen lone pair of electrons must be properly oriented so as to interact with the rhodium carbenoid.84 Thus, subjection of the -oximino isomer 182 to a catalytic quantity of Rh2(OAc)4 in CH2C12 (40 °C) with a slight excess of DMAD afforded the bimolecular cycloadduct 184 in 93% yield. In sharp contrast, when the isomeric Z-oximino diazo derivative 183 was exposed to the same reaction conditions, only indanone-oxime 185 (80%) was obtained. The formation of this product is most likely the result of an intramolecular C-H insertion reaction. 

Gutman,50 in his process route, which did not report any yields, hydrogenated the pyridine ring first to access the piperidine moiety and constructed the indanone ring system via an intramolecular Friedel-Crafts acylation (Scheme 5). Hydrogenation of diester 31, obtained from condensation of 4-pyridine carboxaldehyde and dimethyl malonate, followed by benzylation of the piperidine intermediate afforded A-benzylated piperidine 32. Alkylation of 32 with 3,4-dimethoxybenzyl chloride (33) and subsequent hydrolysis gave dicarboxylic acid 34. Subjection of 34 to strong acid resulted in intramolecular Friedel-Crafts acylation and in situ decarboxylation to provide 3. 

The total synthesis of dihydrolycorine (38), the sole hydrogenation product of lycorine (6 R1 + R2 = CH2, R3 = R4 = H) and an alkaloid in its own right, has been reported.27 Scheme 3 shows how treatment of the Diels-Alder adduct (33) with methanol gave a mixture of two half-esters which were directly subjected to Friedel-Crafts cyclization to give the indanone ester (34) and a rearrangement product. Attempted Schmidt ring expansion on (34) failed, but a prior reduction-oxidation sequence followed by treatment with sodium azide and hydrolysis produced the desired lactam (35) and an isomeric compound whose structure remains undetermined. Lactam (35) was readily converted into a chain-extended... 

Scheme 14 Indanone (146) was converted to alcohol (147). The acetyl derivative of (147) after demethylation was made to react with glyoxal to obtain lactone (149), which reacted with dibromocarbene and diazomethane to yield (150). Its silyl derivative was subjected to ring expansion by radical pathway to obtain cycloheptatriene (151). Its formyl derivative on dehydration gave the natural product lettucenin A.

Analogous decarbonylations have been observed for ketones under ultraviolet irradiation at elevated temperatures. From a preparative point of view the behavior of diphenyl-substituted and a,a-divinyl-substituted ketones is interesting, as they are decarbonylated when their benzene solutions are subjected to ultraviolet irradiation.69 This favorable effect of phenyl sub-stitutents on decarbonylation has been noted also for cyclic ketones for example, under suitable conditions l-phenyl-2-indanone eliminates carbon monoxide and yields 90% of 5,6,ll,12-tetrahydro-5,6-diphenyldibenzo[a,e]-cyclooctene as a mixture of cis- and trans-forms,10 whereas 2-indanone itself is hardly decarbonylated at all in benzene solution. That in other cases decarbonylation is usually more profitable in the gas than in the liquid phase is shown by studies of the photolysis of tetramethyl-l,3-cyclobutanedione which in the gas phase gives 2 equivalents of carbon monoxide and a quantitative yield of 2,3-dimethyl-2-butene.71... 

Bolm s group [56] in 2014 reported the oxidative C-H arylation of acylsilanes with acrylates using [(RhCp Clj)2] (2.5 mol%), AgOTf (10 mol%), Cu(OAc)2 (1.2 equiv) in DCE (Dichloroethane) at 60°C for 24h (Scheme 4.9). The yields were good, the reaction scope broad, and there was good functional group tolerance. These ortfio-olefinated aroylsilanes were then subjected to UV-irradiation and provided valuable indanone derivatives in quantitative yields (Scheme 4.9). 

When the epoxytriones 353 were subjected to FVP, the retro-Diels— Alder loss of cyclopentadiene was accompanied by similar ring expansions to give the benzoquinone-fused pyranones 354 along with the indanone-fused decarbonylation products 355 (Scheme 69 2009JOC1598). 

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