Allyl cyanide, asymmetric

The asymmetric hydroformylation of allyl cyanide has recently focused the interest of researchers because the iso-aldehyde derivative can be easily transformed into 2-methyl-4-aminobutanol, a useful building block, for instance for the asymmetric synthesis of tachikinin (58), a novel NK1 receptor agonist developed by Takeda [82], It should be noticed that this aldehyde is not accessible via the hydroformylation of crotononitrile. 

Table 5 Rh-catalyzed asymmetric hydroformylation of allyl cyanide with ligands 2, 5, 59-62 ...

DSM reported that the asymmetric hydroformylation of unsaturated nitriles (Scheme 12.72) to provide a potential route to (/ )-4-amino-2-methyl-l-ol (180), which is a key intermediate for TAK-637 (181), a new Tachykinin NK, receptor antagonist, developed by Takeda (Scheme 12.73). Rhodium-BINAPHOS (4 equiv) has catalyzed the asymmetric hydroformylation of but-3-enenitrile (allyl cyanide) with regioselectivity of 72/28 (b/1) and 66% ee at 73% conversions.227... 

Klosin and co-workers at Dow Chemical have reported a parallel protocol for the screening of asymmetric hydroformylation reactions of styrene, vinyl acetate, and allyl cyanide.In a one-pot, multiple substrate screening method introduced by Kagan, an Endeavor eight-cell reactor was used to screen 48 different rhodium... 

I 4 C-C, C-O, and C-B Bond Formation by Pincer Complexes Including Asymmetric Catalysis Table 4.2 Catalytic allylation of imines with allyl cyanides. 

An exception concerns probably the asymmetric hydroformylation of allyl cyanide with a chiral monodentate phos-phoramidite ligand, which gave 80%... 

Scheme 4.84 Asymmetric hydroformylation of allyl cyanide and subsequent steps to a building block with the potential for the construction of pharmaceutically interesting compounds.

On the basis of this finding, Shibasaki s group developed a series of asymmetric reactions using soft copper(I) Brpnsted base catalysts and a wide variety of pre-nucleophiles (thioamides [34 3], isocyanide [44, 45], unsaturated butyrolactones [46, 47], nitroalkanes [48], allyl cyanide [49, 50], and a-trifluoromethylacetamide [51]) via proton transfer strategy (Fig. 5). 

Fig, 38 Asymmetric addition of allylic cyanide to ketoimines and ketones... 

Cobley CJ, Gardner K, Klosin J, Praquin C, HiU C, Whiteker GT, Zanotti-Gerosa A, Petersen JL, Abboud KA. Synthesis and application of a new bisphosphite ligand collection for asymmetric hydroformylation of allyl cyanide. J. Org. Chem. 2004 69 4031 040. 

Pyridine A-oxides have been utilized as asymmetric catalysts in the allylation of aldehydes <06JOC1458> and in the Strecker reaction <06T4071>. In the latter, the chiral A-oxides played a key role in the initial activation of the Si-C bond by coordinating an O atom to the Si atom of silyl cyanide and stabilizing the three-membered complex proposed by the... 

Methoxyoxazolidines (464) are useful for the asymmetric formylation of various nucleophiles including silyl enol ethers (92X6011), trimethylsilyl cyanide (93SL921), enamines (90TL4223), and allyl silanes. 

Many other reports of ligand libraries for specific catalytic applications have been reported. Among them, Gilbertson and co-workers reported a chiral phosphine library, tested in the rhodium-catalyzed asymmetric hydrogenation of an enamide (158,159), and a similar library for the palladium-catalyzed allylation of malonates (160, 161) Hoveyda and co-workers (162, 163) reported a chiral Schiff base library, screened in the titanium-catalyzed opening of epoxides with (TMSCN) (trimethyl silyl cyanide) ... 

Tridentate salen ligands (10) derived from 1 have given excellent results in the enantiocontrol of the hetero Diels-Alder addition reaction of dienes with aldehydes (eq 7) and in the asymmetric additions of TMS-azide to mc5o-epoxide and trimethylsilyl cyanide to benzaldehyde (up to 85% ee). Phosphino-oxazolines derived from 1 have been employed for the asymmetric control of palladium-catalyzed allylic substitution reactions products of 70-90% ee were obtained. Photolysis of crystalline adducts of enantiomerically pure 1 with prochiral alcohols results in asymmetric inductions of up to 79% in a rare example of a solid-state enantioselective reaction. ... 

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