Trans-2-Amino-1 -hydroxy-1 -methyl

Recently, it was found that the addition of benzylamine to 2-(5//)-furano-3-ylmethanesulfonate 280 (X = O—SOaMe) in methanol afforded a 7 1 mixture of the trans- and cw-methyl-A-benzyl-2-hydroxymethylaziridine-2-carboxylates 281 and 282, respectively (00TL3061). Treatment of 281 with benzyl alcohol in the presence of BF3 OEta furnished, after hydrolysis, rac-cw-amino-a-hydroxy-/3-butyrolactone 284 (Scheme 74). 

Another chiral auxiliary for controlling the absolute stereochemistry in Mukaiyama aldol reactions of chiral silyl ketene acetals has been derived from TV-methyl ephedrine.18 This has been successfully applied to the enantioselec-tive synthesis of various natural products19 such as a-methyl-/ -hydroxy esters (ee 91-94%),18,20 a-methyl-/Miydroxy aldehydes (91% ee),21 a-hydrazino and a-amino acids (78-91% ee),22 a-methyl-d-oxoesters (72-75% ee),20b cis- and trans-l1-lactams (70-96% ee),23 and carbapenem antibiotics.24... 

Dec-trans-4-enoic acid, 3-hydroxy-6-iso-pro-pyl-3-methyl-9-oxo, (6S) Lf 0.037 Dec-trans-4-enoic acid, 3-hydroxy-6-iso-pro-pyl-3-methyl-9-oxo Lf 0.008 Dehydratase, A-amino-levulinic acid ... 

R = H trans-2-Amino-l-hydroxy-cyclohexan HC1 R = CH3 trans-l-Amino-2-hydroxy-l-methyl-cyclohexan - HC1... 

The chemical shifts for hydrogens and methyl groups at C-4 of 5-hydroxy-and 5-amino-A2-1,2,3-triazolines depend on the orientation relative to the hetero substituent at C-5. This has been extensively used for assignment of relative configurations at C-4 and C-5 of variously substituted A2-tria-zolines.216,259 lH-NMR spectra show that 5-alkoxy- and 5-hydroxy-A2-1,2,3-triazolines prefer an envelope conformation218 (63) with the hetero substituent at C-5 pseudoaxial at the flap and the N-l substituent pseudoequatorial, probably because of the anomeric effect. The cis and trans coupling constants in the 5-amino-, 5-hydroxy-, and 5-aIkoxy-A2-l,2,3-triazolines are very constant, being 7.0-9.8 and 2.0-3.4 Hz, respectively.218... 

OHDPAT, 8-hydroxy-2(di- -propylamino)tetralin ACPD, trans-1 -amino-cyclopenty 1 -1,3 -dicarboxylate AMP A, DL-cr-amino-3-hydroxy-5-methylisoxazole-4-propionate BIMU8, [endo-A-8-methyl-8-azabicyclo(3.2.1)oct-3-yl]-2,3-dihydro-3-isopropyl-2-oxo-177-benzimidazol-l-carboxamide hydrochloride CGP 35348, 3-aminopropyl(diethoxymethyl)phosphinic acid CNQX, 6-cyano-7-nitroquinoxaline-2,3-dione CP 99994, (+)-(2 , 3A)-3-(2-methoxybenzylamino)-2- ... 

The most revealing study of the deamination of amino alcohols was carried out by Shoppee on the four epimeric i7-amino-i7a-hydroxy-i7a-methyl-D-homoandrostanes [307. The product from each of these compounds was predictable in terms of a trans coplanar 4-centre transition state, and the outcome of each reaction was entirely analogous to the result expected from hydrolysis of a halohydrin fixed in the same... 

Ala = Alanine, 6-Br-Trp = 6-bromotryptophan, Dide-Phe = a,P-dide-hydro-3,4,5-trihydroxyphenylalanine, Dide-Val = a,P-didehydro-valine, diOH-Sty = 3,4-dihydroxy-trans-styrylamine = [( )-l-amino-2-(3,4-dih-ydroxyphenyl)ethene], Gly = Glycine, lieu = Isoleucine, Leu = Leucine, N-Me = A-methyl, N,N-diMe = A,A-dimethyl-, P-OH = P-hydroxy, OH-Sty = 4-hydroxy-tra s-styrylamine = [( )-l-amino-2-(4-hydroxypheny-l)ethene], Phe = Phenylalanine, Phe-Et = Phenylethylamine, Pro= Proline, Sty = Styrylamine, Trp = Tryptophan, Tyr = Tyrosine, Val = Valine. 

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