Page 608 - Advanced Organic Chemistry Part B - Reactions & Synthesis

582 The reactions occur preferentially though an endo TS in which the sulfur substituent
is oriented toward the allylic group. 273 Computational studies (MP2/6-31G ) found the
∗
CHAPTER 6 endo TS to be favored over the exo by 1.5–2.2. kcal/mol. 274
Concerted
Cycloadditions,
Unimolecular R
Rearrangements, and S O S O
Thermal Eliminations
R
endo TS exo TS

The allyl sulfoxide–allyl sulfenate rearrangement can be used to prepare allylic
alcohols. 275 The reaction is carried out in the presence of a reagent, such as phenylthi-
olate or trimethyl phosphite, that reacts with the sulfenate to cleave the S−O bond.

O –
OSPh PhS – OH
(CH 3 ) 3 C CHCH 2 SPh (CH 3 ) 3 C (CH ) C
3 3
+ CH CH 2 CH CH 2
95%
Ref. 276
An analogous reaction occurs when allylic selenoxides are generated in situ by
oxidation of allylic selenyl ethers. 277

H 2 O 2
PhCH 2 CH 2 CHCH CHCH 3 PhCH 2 CH 2 CHCH CHCH 3 PhCH 2 CH 2 CH CHCHCH 3
SePh OH
SePh
O

CO CH 3 HO CO CH
2
O 2 O 3
30% H O
O 2 2 O
10°C
ArSe
68%
Ref. 278
N-Allylamine oxides represent the general pattern for [2,3]-sigmatropic
−
rearrangement where X = N and Y = O The rearrangement provides O-allyl hydrox-
ylamine derivatives.
PhCH CHCHCH 3 –20°C PhCHCH CHCH 3
+
N (CH ) 24 days (CH 3 ) 2 NO
3 2
– O
Ref. 279

273 P. Bickart, F. W. Carson, J. Jacobus, E. G. Miller, and K. Mislow, J. Am. Chem. Soc., 90, 4869 (1968).
274
D. K. Jones-Hertzog and W. L. Jorgensen, J. Am. Chem. Soc., 117, 9077 (1995).
275 D. A. Evans and G. C. Andrews, Acc. Chem. Res., 7, 147 (1974).
276 D. A. Evans, G. C. Andrews, and C. L. Sims, J. Am. Chem. Soc., 93, 4956 (1971).
277
H. J. Reich, J. Org. Chem., 40, 2570 (1975); D. L. J. Clive, G. Chittatu, N. J. Curtis, and S. M. Menchen,
Chem. Commun., 770 (1978).
278 P. A. Zoretic, R. J. Chambers, G. D. Marbury, and A. A. Riebiro, J. Org. Chem., 50, 2981 (1985).
279
Y. Yamamoto, J. Oda, and Y. Inouye, J. Org. Chem., 41, 303 (1976).