Reagents, xiii

This reaction cycle is characterized by the use of hypervalent iodine species XII as the stoichiometric oxidant and a catalytic quantity, around 0.2 mol, of the oxidizing azo reagent XIII. The benefit of using XII is that the by-products, iodobenzene and acetic acid, are relatively simple to remove, while at the same time, the amount of hydrazine by-product XI formed is dramatically reduced. Under optimized conditions, the authors obtained aryl-carboxylic acid esters with chiral alcohols in 65% yield and with 100% e.e. 

Xb was utilized in the elaboration of the hydrindan XIII and subsequently compound XIV. We expected that Xa could be converted to XIII in the same manner as was in the Sih synthesis. This was confirmed in practice (Scheme II). Oxidation of 569 mg (2.68 mmol) of Xa with pyridinium chlorochromate in methylene chloride furnished 532 mg (94%) of enone Ila (7,21). Treatment of 130 mg of Xa witlj a slight excess of Jones reagent (3,22) afforded 126 mg (98%) of Ila. Allylic brominatlon of Ila with a 20% excess of N-bromosuccinimide (NBS) in refluxing carbon tetrachloride provided Xlla in 98% yield. 

Scheme 31. Reagents i, TsOH cat. ii, LiAIH4 iii, CICOOBn, THF, H2O iv, AcCl v, KCN vi, H2O2, NaOH vii, MeOH, Amberlist 15 viii, H2, Pd-C ix, CICOOBn x, MsCI, Et N xi, BuOCl xii, vindoline, BF3 Et20 xiii, Na2COv...

Reagents i, LiNPr a-DME ii, Mel iii, Br(CH2)40THP-HMPA iv p-TsOH-MeOH v, Ca-NHj-THF-HMPA vi, CrOj-HjO -MeaCO vii, CHjNj viii, NaNiSiMcjlj-DME ix, HCI,0°C x, DBU-xylene, A xi, silica gel-15% AgN03 xii, CH2=PPli3-DMSO xiii, MeOH-H xiv, HCI gas-CH2Cl2 xv, collidine. A xvi, LiAlH4 xvii, 10% NaOH xviii, Li-NH3-EtOH... 

Scheme 1. Preparation of oxo complexes. Reagents (i) NH3, (ii) RNH2 (R = tertiary alkyl group), (iii) RN=PPh3, (iv) RNH—SiMe3, (v) NR3, (vi) reductant, nonaqueous solvent (vii) excess L, (viii) excess HX, (ix) OH, (x) nonreducing acid, (xi) reductant, (xii) excess HX or X-, (xiii) L, (xiv) hv plus reductant or electrochemical reduction, (xv) R C=CR5, (xvi) L = py, etc., (xvii) oxidation of Os(II), Os(III), or Os(IV) complexes, and (xviii) A...

XIII. Treatment with Alkali-Acetone Reagent. Dissolve in a test tube ca O.lg of the sample in ca 5ml of acetone, add ca 2ml of 10% NaOH soln and shake the mixt. After allowing to stand for lmin, note the color. A blue color indicates DNT and its presence may be confirmed by M-D(Meyer-Drutel) Test, which would give purple-red. A viol color indicates DNB which would give red-brn by M-D test. A light red indicates PETN, which would give with benzylamine no color(See item VII). A deep red indicates Tetryl, which would give with... 

Ammonals, which are mixts of AN, TNT A1 (See Vol l,p A287),give a brn ppt with Nessler s Reagent(See items M XII) and a deep red color with Alkali-Acetone Reagent(See item XIII).These tests do not indicate, however, if A1 is present... 

Pentolite, which is a blend of PETN with TNT, produces a red color with Alkali Acetone Reagent(See item XIII) and a red color with Franchimont s Reagent(See item XlV)(See also Charts A B)... 

Some colorimetric detns of ingredients of proplnts using Muraour s reagent(See item L) 18)Jabobs(l949), Chap XIII(Colorimetric tests for various org compds which include many expls 8c their primary materials) 18a)T.C.J. Ovenston, JSCI 68,... 

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