2-Allyl-2-mcthyl

Displacement of secondary allyl halides is satisfactory for the formation of symmetric allylstannanes, e.g., ( )-tributyl(l-mcthyl-2-butcnyl)stannane17, but can give 1,3-rearranged products in other cases, e.g., from 3-chlorobutene and trimethyltin reagents14 lS. Allylic cyclohexenyl chlorides react with triphenyltin lithium with clean inversion and little 1,3-transformation19,20. 

S) und (R )-a-Allyl-a/anin (2-Amino-2-methyl-4-pentensaure)1 (5- und (R)-u-Methyl-phenylalanin1 (2S.4S)- und (2S,4J )-4-Mcthyl-glutaminsaure3 (2S,3S)- und (2S,JR)-t-Phenyl-glutaminsaure3... 

SCHEME 4.5 1,2-Migration in the stereoselective synthesis of 1, 2-tram (amino)-glyco-sides and 2-deoxyglycosides as reported by (a) Danishefsky, (b) Yu, and (c) Lowary. Ac, acetyl All, allyl Bn, benzyl Bz, benzoyl DTBMP, 2,6-di-fert-butyl-4-mcthyl pyridine TBDPS, ferf-butyldiphenylsilyl THF, tetrahydrofuran TIPS, triisopropylsilyl Tol, 4-tolyl. 

The success of the cyclization is dependent on the nature of R1 and the /V-substituent R1 can be an alkyl or, preferably, aryl group, although not with great steric bulk, whereas only the iV-mcthyl substituent achieves satisfactory yields. Cyclization of 3-butenylamides was not successful, and cyclization of the 5-hexenylamide failed as abstraction of the allylic hydrogen is the preferred path for the aminyl radical, leading to double-bond isomerization. 

Synthesis ofkarahanaenaue. The ionic reaction of NBS in CCI4 at room temperature with a y-ethylcnic tertiary alcohol leads to an -bromotetrahydrofurane. The reaction has been used in a convenient synthesis of karahanaenone (4), a constituent of hop oil, from linalool (1). Thus reaction of (1) with NBS affords 2-mcthyl-2-vinyl-5-(l-bromo-l-methylethyl)tetrahydrofurane (2) in 85% yield. Dehydrohalogena-tion of (2) with collidine at 110 leads to the allyl vinyl ether (3), which immediately... 

Chlor-allyl)-3,5-dimeLhyl- 426 3(5)-(4-Chlor-benzoyl)-503 4-(2-Chlor-benzoyl)-5-hydroxy-3-mcthyl- 669 Chlorcarbonyl- 654 4-Chlorcarbonyl- 625 l-Chlorcarbonyl-3,5-dimethyl- 647... 

Thus, the bifunctional allylic diol 12 was reacted with 2-methoxy-3-mcthyl-l,3-butadiene in refluxing xylene in the presence of an acid and reduced with sodium borohydride to give 2,6.11,15-tetramcthyl-l,6,10,15-hexadecatetraene-3.14-diol (13), which can be transformed to the symmetrical triterpene squalene28-224. 

N Mcthyl>N.O>bts(irimetbylttl>t)-hydroxybmme, 187 Amines stf aiCio Allylic oompouiMh. Amino acidt. Amino alcohols. Amino carbonyl compounds. Amino nitnles. Enamiocs. Momoallylk amines)... 

AUyiation of 2-methylnaphthohydroquinone-l,4. Japanese chemists have found that ) -cyclodextrin can play a significant role in the allylation of 2-methyl-naphthohydroquinone-l, 4. Thus condensation of allyl bromide with the hydro-qiiinone in dilute aqueous alkaline solution in the presence of -cyclodextrin results in 2-mcthyl-3-allyl-l, 4-naphthoquinone (equation I) in yields of 82-927o- The... 

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