Tert Butyl diazoacetate

Buten-l-yl diazoacetate, 2377 tert-Butyl diazoacetate, 2423 tert-Butyl 2-diazoacetoacetate, 3009 5-/er/-Butyl-3-diazo-3//-pyrazole, 2831 Cyanodiazoacetyl azide, 1346 5-Cyano-4-diazo-4//-l,2,3-triazole, 1345 Diazoacetaldehyde, 0710 Diazoacetonitrile, 0675 Diazoacetyl azide, 0679... 

Katsuki has recently constructed a series of chiral Co(III)-salen complexes 30 and used them as catalysts for cyclopropanation of styrene using tert-butyl diazoacetate [78], Not only is enantiocontrol for addition greater than 90% ee, but diastereoselectivity favors the trans-... 

The group of Arai and Nishida investigated the catalytic asymmetric aldol reaction between tert-butyl diazoacetate and various aldehydes under phase-transfer conditions with chiral quaternary ammonium chloride 4c as a catalyst. The reactions were found to proceed smoothly in toluene, even at —40°C, when using 50% RbOH aqueous solution as a base, giving rise to the desired aldol adducts 23 with good enantioselectivities. The resulting 23 can be stereoselectively transformed into the corresponding syn- or anti-P-hydroxy-a-amino acid derivatives (Scheme 2.20) [42],... 

A dry test tube containing catalyst (1.4 mg, 2 pmol, 2 mol%) and the imine (44.4 mg, 0.15 mmol, 1.5 equiv) was purged with nitrogen and then charged with toluene (1 mL). The resulting solution was treated with neat tert-butyl diazoacetate (14.2 mg, 0.1 mmol, 1 equiv) at r.t. After stirring for 24 h at ambient temperature, the mixture was subjected directly to FC on silica gel (hexanes ethyl acetate, 10 1 to 3 1) to give the product (32.9 mg, 75 pmol, 75% yield, 95% ee) as an oil. 

The substitution pattern in the product obtained through this sequence was in agreement with the proposed mechanism (Table 3.7). For example, crotyl chloride gave the 2-chloro-3-methyl hex-4-enoates (entries 3 and 4), and propargyl bromides gave the allenic products (e.g., entries 7 and 8). Yields were usually better with the more substituted tert -butyl diazoacetate. 

Diazoacetic acid silyl esters can be prepared by fra t-esterification of tert-butyl diazoacetate with trialkylsilyl triflate <1985JOM33>. Analogously prepared (alkenyloxy)silyl 203 and (alkynyloxy)silyl diazoacetates 206 underwent silicon-tethered 1,3-dipolar cycloaddition reactions as shown in Scheme 37 and Equation (38). Compound 205 resulted from a lateral criss-cross cycloaddition of the intermediate azine 204, which was formed from two molecules of 203 by diazo + diazo or diazo + carbene reaction <2000T4139>. On the other hand, when silyl diazoacetates 206 were kept in xylene at 142 °C for 1 h, bicyclic pyrazoles 207 were obtained (Equation 38). 

Aryl-5,5-bis(oxazolin-2-yl)-l,3-dioxanes 169 have been easily prepared in three steps from diethyl bis(hydroxymethyl)malonate, amino alcohols, and aromatic aldehydes. They have been used for the copper-catalyzed asymmetric cyclopropanation of styrene with ethyl diazoacetate in up to 99% ee for the trawx-cyclopropane (maximum transicis ratio = 77/23) <05TA1415>. The same reaction performed on 2,5-dimethyl-2,4-hexadiene with tert-butyl diazoacetate in the presence of copper catalysts bearing ligand 170, prepared from arylglycines, exhibited remarkable enhancement of the rrawx-selectivity (transicis ratio = 87/13), with 96% ee for the trans product <05JOC3292>. 

Ishitani and Achiwa [16] have recently prepared an axially disymmetric rhodium (11) biphenylcarboxylate catalyst, Rh2(S-BDME)4 of Fig. 2, and found that although the transxis diastereoselectivity in its catalysis of the styrene-EDA reaction was poor, the enantiocontrol was better than that observed with the pro-linate catalyst. The biphenyl based catalyst yielded an 87% ee for the cyclopro-panation of 2-naphthylethene and tert-butyl diazoacetate, though again the diastereoselectivity was very low. Use of an additional chiral auxiliary in the diazoester as in the d-menthyl derivative in Eq. (10) furnished a mixture of cyclopropanes, the cis-isomer of which was found to have an ee of 99%. 

Subsequently, Maruoka group developed an enantioselective 1,3-dipolar cycloaddition reaction between diazoacetates and a-substituted acroleins (Scheme 1.20) [24d]. The reactions of 1.5 equivalent of ethyl or tert-butyl diazoacetate and various a-substituted acrolein derivatives afford chiral 2-pyrazolines with high... 

In additimi to EDA, a more bulky diazo reagent, tert-butyl diazoacetate (t-BDA), was found to be suitable for the catalytic system, generating the corresponding tert-butyl a, -unsaturated esters 21 with comparable yields (73-94%) and E-selectivity (E/Z 62/38-99/1) (1) ... 

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