Cyclo-SEM: A new carbonyl protecting group

Tetrahedron Letters

Volumn 38, Issue 11, 1997, Pages 1873-1876

  Lipshutz, Bruce H ^a   Mollard, Paul ^a   Lindsley, Craig ^a   Chang, Virginia ^a  

^a UNIVERSITY OF CALIFORNIA   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

1,3 DIOXANE DERIVATIVE; ACETAL DERIVATIVE; CARBONYL DERIVATIVE; FUNCTIONAL GROUP;

ARTICLE; CHEMICAL REACTION; CHROMATOGRAPHY; NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY; PROTECTION; REACTION ANALYSIS; SYNTHESIS;

EID: 0031575812     PISSN: 00404039     EISSN: None     Source Type: Journal    
DOI: 10.1016/S0040-4039(97)00239-6     Document Type: Article

References (11)

1. 1. Greene, T.W.; Wuts, P.G.M. in Protective Grougs in Organic Synthesis, Wiley, N.Y., 1991, 2nd Ed.; Kocienski, P.J. Protecting Groups, Thieme, Stuttgart, 1994.
2. 2. Lipshutz, B.H.; Pegram, J.J. Tetrahedron Letters, 1980, 21, 3343.
3. 3. For a related protecting group, see Lillie, B.M.; A very, M.A. Tetrahedron Letters, 1994, 35, 969.
4. 4. Boeckman, R.K.; Blum, D.M.; Ganem, B.; Halvey, N. Org. Syn. Coll Vol. VI, 1988, 1033.
5. 5b although subsequent reaction with paraform-aldehyde leads to alcohol 5 in 35-71% yield;
6. (b) Overman, L; Renhowe, P.A. J. Org. Chem., 1994, 59, 4138.
7. 6. Use of alternative hydroborating agents, such as 9-BBN, led to inferior results.
8. 4 (in THF or DMPU).
9. 3CN removes the cyclo-SEM group very easily, although in our hands, this reagent/solvent combination, in control experiments, also deprotects standard dioxane and dioxolane derivatives.
10. 4 in refluxing THF, gave only small percentages of ketone, presumably from traces of adventitious water.
11. 10. For a recent alternative method for acetal unmasking under neutral conditions, see Johnstone, C.; Kerr, W.J.; Scott, J.S. J. Chem. Soc., Chem. Commun. 1996, 341.