One-pot two-step synthesis

Both regioisomers were observed in aminohydroxylation of almost all the substrates that were examined. By taking advantage of their high combined yields, as well as the racemic nature of the aminohydroxylation products, a one-pot, two-step synthesis of sulfonyl aziridines through the cyclodehydration of hydroxysulfona-mides was developed (Scheme 12.18). 

Krauueer, M., Hummel, W. and Groeger, H. (2007) Enantioselective one-pot two-step synthesis of hydrophobic allylic alcohols in aqueous medium through the combination of a Wittig reaction and an enzymatic ketone reduction. European Journal of Organic Chemistry, (31), 5175—5179. 

In the same year, Enders and coworkers reported an asymmetric one-pot, two-step synthesis of substituted isoindolines 159 in the presence of chiral A-triflyl phosphoramide (R)-Ae (10 mol%, R = d-NO -C H ) (Scheme 67) [87]. The cascade was triggered by a Brpnsted acid-catalyzed aza-Friedel-Crafts reaction of indoles 29 and A-tosyliminoenoates 160 followed by a DBU-mediated aza-Michael cyclization of intermediates 161 to afford the isoindolines 159 in high yields (71-99%) and short reaction times (10 min to 4 h) along with good enantioselectivities (52-90% ee). Longer reaction times (16 h to 10 days) caused increasing formation of the bisindole byproduct 162 (Scheme 68) along with amplified optical purity of isoindolines 159. 

A convenient, one-pot, two-step synthesis of l-azabicyclo[1.1.0]butane (5, R = H) from f -chlorosuccinimide is reported and its application to the synthesis of 133-tnnitroazetidine (TNAZ) is discussed <98SC3949>. Another novel and efficient synthesis of 1-aza-bicyclo[1.1.0]butane (5, R = H) and its derivatives is from 23-dibromopropylamine. The bicyclic 5 (R = H) is also useful in the synthesis of the pendant group of a ip-methylcarbapenem antibiotic <99TL3761>. The reaction of 5 (R = Et and Ph) with tosyl chloride and tosyl azide are described <98T15127,99H131>. 

A one-pot, two-step synthesis of a wide variety of pyrazolo[3,4-3]pyridines has been reported by Zheng in situ diazo transfer followed by Friedlander cyclization affords good yields of the desired products (Equation 54 Table 30) <2006SC1549>. 

Liu and co-workers have developed an efficient three-component, one-pot, two-step synthesis of 3ff-quinazolin-4-ones from readily available carboxylic acids and amines [ 124] (Scheme 49). The versatility of the methodology is remarkable. Simple variation of the starting materials allows not only for the decoration of the quinazolin-4-one core with diverse substituents, but also... 

Several variations of this concept have been reported.50-52 For example, Ley and Priepke50 prepared the trisaccharide unit, which is derived from the common polysaccharide antigen of a group B Streptococci by a facile one-pot two-step synthesis (Scheme 4.18). In this... 

Argiiello, J.E., Schmidt, L.C. and Penenory, A.B. (2003) One pot two-step synthesis of aryl sulfur compounds by photoinduced reactions of thiourea anion with aryl halides. Organic Letters, 5, 4133—4136. 

Fig. 46 One-pot two-step synthesis of allylic alcohols. The reductive step is catalyzed by (R)-ADH from Lactobacillus kefir or by (S)-ADH from Rhodococcus sp., respectively. The coenzyme is regenerated by an excess of isopropanol...

Recently, Wasserscheid and co-workers [103] introduced a complementary method for functionalized ionic liquid synthesis (11). In a one-pot, two step synthesis, the protonation of an imidazolium or pyridinium cation followed by a Michael-type addition to methyl vinyl ketone was reported. The only drawback is the limited thermal stability of the cations, which at moderately elevated temperatures undergo a retro-Michael reaction ... 

M. Adachi, H. Tanaka, and T. Takahashi, An effective sialylation method using N-Troc and N-Fmoc-protected /i-thiophenyl sialosides and application to the one-pot two-step synthesis of 2,6-sialyl-T antigen, Synlett, (2004) 609-614. 

Generality of this mechanochemical protocol was demonstrated in one-pot, two-step synthesis of triazole (Scheme 3.102). The first synthetic step, 1,3-dipolar cycloaddition ( click reaction ) of 4-iodobenzyl azide with phenyl acetylene employing copper powder (1 equiv.) was complete in lOmin and follows the synthetic procedure described in chapter Cycloaddition Reactions [67], Ullmann Af-arylation of tiiazole 371 with ethylenediamine in optimized reaction conditions provided the corresponding W-arylated triazole 372 in 56% yield, albeit reaction required 2h of ball milling to complete. 

Scheme 9. One-pot two-step synthesis of trisaccharide 57 using glycosyl donor...

A mild and convenient one-pot two-step synthesis of hydroxystilbenes ( )-4-chloro-4 -hydroxy-3 -methoxystilbene from 4-hydroxy-3-methoxybenzaldehyde and 4-chlor-ophenylacetic add with trans selectivity developed through a modified Perkin reaction between benzaldehydes and phenylacetic adds was recently reported (Figure 1.12) [67j. 

A one-pot two-step synthesis of hydroxystilbenes with trans selectivity was developed through a modified Perkin reaction between benzaldehydes and phenylacetic acids bearing 4- or 2-hydroxy substitution at the aromatic ring [67]. The reaction was performed under mild conditions in the presence of piperidine-methylimidazole and polyethylene glycol under microwave irradiation. As a result, 71% yield of ( )-4-chloro-4 -hydroxy-3 -methoxystilbene from 4-hydroxy-3-methoxybenzaldehyde and 4-chlorophenylacetic acid was obtained. A microwave-induced one-pot process for the preparation of arylethenes has been patented [118]. For the preparation of a series of arylethenes (I R -R = H, OH, OMe, AcO, halo, NO2 R, R, R = OH, AcO R= H, substituted aryl), reaction of 2- or 4-hydroxy substituted cinnamic adds or derivatives in the presence of a base, under reflux or microwave irradiation, has been used. For example, a mixture of a-phenyl-4-hydroxy-3-methoxycinnamic acid, NaHC03, methylimidazole, and polyethylene glycol was microwaved at 200 W and 180 °C for 10 min to give 96% 4-hydroxy-3-methoxystilbene. 

Creenia and Horaguchi also explored the Cadogan reaction for the synthesis of a variety of W-containing heterocycles. With the aide of microwave, a less reactive and less toxic triphenylphosphine could be used in place of triethyl phosphite. For example, a one-pot, two-step synthesis of benzimidazole 26 was accomplished by microwaving (200 W) a mixture of... 

Beneteau, V., Olmos, A., Boningari, T., Sommer, J., and Pale, P. 2010. Zeo-cbck synthesis Cu -zeolite-catalyzed one-pot two-step synthesis of triazoles from halides and related compounds. Tetrahedron Lett. 51(28) 3673—3677. 

The copper(I)-catalyzed synthesis of 1-sulfonyl triazoles and their subsequent transannulation with nitriles can be combined into a one-pot two-step synthesis, thus further simplifying the experimental procedure (Scheme 7.12). The catalytic amount of copper remaining in the reaction mixture after the first step evidently does not interfere with the formation or reactivity of the carbene complex. 

Scheme 7.12 One-pot two-step synthesis which converts sulfonyl azides, terminal alkynes, and nitriles into imidazoles. The only byproduct of the reaction is a molecule of dinitrogen.

Indole-fused pyran-4-ones are prepared in one-pot two-step synthesis. In the first there is the acylation of 1-substituted 3-acetyl-lH-indol-2-ols with acid chlorides using triethylamine as base, in dichloromethane at room temperature. The second consists in the 4ff-pyran-4-one ring formation firom the in situ-obtained 3-acetyl-2-acyloxy-lF/-indole derivatives (13S1235).A highly diastereo- and enantioselective organocatalytic formal hDA reaction of enones with isatins occurs in the presence of amine 34, acid 35, and thiourea 36 to produce spirooxindole tetrahydro-4ff-pyran-4-ones (Scheme 59) (13CEJ6213). 

Keywords Methyl levulinate, primary amines, isocyanides, azidotrimethylsilane, methanol, dichloromethane, room temperature, one-pot, two-step synthesis, Ugi reaction, 1,5-disubstituted tetrazoles, his-pyrrolidinone tetrazoles... 

Grirrane, A., Corma, A. and Garcia, H. (2009). Highly Active and Selective Gold Catalysts for the Aerobic Oxidative Condensation of Benzylamines to Imines and One-Pot, Two-Step Synthesis of Secondary Benzylamines, J. Catal, 264, pp. 138-144. 

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