Cydohexadiene 2-methyl-

In a similar way to the addition of zirconacyclopentadienes to DMAD, their addition to methyl maleate gives cydohexadiene derivatives. It is noteworthy that the two COOMe groups are cis in the starting material and trans to one another in the product, as shown in Eq. 2.63 [7k]. 

In Einzelfallen bietet sich die Ugi-Reaktion fur die Synthese bestimmter a-Amino-carbonsauren im Vergleich zu anderen Moglichkeiten als Methode der Wahl an. Beispiele sind die Herstellung von Bis-[l-carboxy-alkyl]-aminen I aus a-Amino-carbonsaure-estern8 [unter Verwendung von 4-Methyl-phenylsulfonylmethyl-isocyanid (TOSMIC)9 als Isonitril-Komponente] und die von 3-(2,5-Cyclohexadienyl)-alanin-methylamid(ll) (37% aus 3-Formylmethyl-l,4-cydohexadien)1. 

Aminophenyl)(4-imino-2,5-cydohexadien-l-ylidene)methyl]-N-phenyl aniline, monohydrochloride [68966-31-4]... 

FLUORINECOMPOUNDS,INORGANIC - BORON - BORON TRIFLUORIDE] (Vol 11) N- 4-(Bis[4-(phenylammo)phenyl]methylene)-2,5-cydohexadien-l-ylidene -3-methyl-benzeneamme sulfate [57877-94-8]... 

Methyl 6-hydroxy-3-methylhexanoate is our 1,6-difunctional target molecule. Obvious precursors are cyclohexene and cydohexadiene derivatives (section 1.14). Another possible starting material, namely citronellal, originates from the magic box of readily available natural products (C.O. Overberger, 1967, 1968 E.J. Corey, 1968D R.D. Clark, 1976). 

Benzoyl-4-methylbicyclo[2.2.2]oct-5-en-2-one 71, prepared by the Diels-Alder reaction of 2-trimethylsioxy-4-methyl-l, 3-cydohexadiene with benzoylethyne, underwent ODPM rearrangement in the absence of a sensitizer to give 72 in good yield (Scheme 4.29). The irradiation of 72 in 40% triethylamine (TEA)-methanol gave a bicyclo[3.2.1]octanone 73 in 86% yield. On direct irradiation, a one-pot conversion... 

The efficiency of haloboranes as Lewis add catalysts and the sensitivity of the boron atom environment to steric hindrance (see Chapter 6) make boron compounds useful chiral catalysts. Hawkins and Loren [779] prepared enantiopure chloroborane (17 ,2I )-3.6, and they showed that the complex 3.6 with methyl crotonate lies under the s-trans conformation 9.40 both in the solid state and in solution. This conformation is also the reactive one, and [4+2]-cycloadditions of acrylates with cyclopentadiene or cydohexadiene catalyzed by (17 ,2i )-3.6 lead highly selectively to the product resulting from the attack of the diene on the unshielded face of complex 9.40 (Figure 9.15). 

THBA from butadiene 2,5-c Wtf-methylene from 1,3-cydopentadiene 4-methyl- PH B A from 2-methylbutadiene 2,5-tW< -etliylene from 1,3-cydohexadiene. 

Dimethyl-hexatrieu-(l,3,5) 3-[3-Methyl-buten-(l)-yl-(2) -cydobuten + l,4-Dimeihyl-cydohexadien-(l, 3) 4... 

Methyl-l-i opropyl-cydohexadien-(l,3) - -4-Methyl l-isopropyl-bicyclo[2.2.0] — ... 

Heck reactions catalyzed by 10, performed with phenyl bromide and n-butyl acrylate in NMP at 140 °C with 0.01 mol% of catalyst and K2CO3 as base. Whereas dramatically retarded conversion rates were observed with the phosphine-based pincer complex 21 in the presence of l-methyl-l,4-cydohexadiene [42], only a marginal effect was noticed under identical reaction conditions with catalyst 10 (as well as with 3). These results exclude the possibihty that the catalyticaUy active species derived from 10 (or 3) and from 21 are of the same type, and in turn imply that different reaction mechanisms can indeed be operative with different pincer complexes in Heck reactions (and most probably also in other cross-coupling reactions). Therefore, its reasonable to anticipate that palladium pincer Heck catalysts can operate via homogeneous (Pd /Pd ) mechanisms and serve as sources of palladium nanopartides, depending on the reaction conditions applied. 

CjgHigCISigOg 6-CUor-2.5.6-tiiiiitro-l-methyl- isopropy l-cydohexadien-(l. 4)-Oii-(3) 71100. 

Amino-5-[(4-amino-3-sulfophenyl) 4-imino-3-sulfo-2,5-cydohexadien-l ylidene)methyl -3-methylbenzenesulfonic acid. Acid magenta. Acid rubin. C.I. Acid violet 19. C.I. 42685. Acid roseine. Acid fuchsine... 

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