Selective Prins Reaction of Styrenes and Formaldehyde Catalyzed by 2,6-Di-tert-butylphenoxy(difluoro)borane

Abstract

The sterically congested Lewis acid 1 was used as a catalyst in the Prins reaction of various styrenes and formaldehyde. 4-Aryl-1,3-dioxanes 5 were selectively formed as the exclusive products of the reaction with styrenes 4a-i and vinylthiophenes 4j-k. The reaction proceeded in most cases with good to excellent yields (55-99%). Styrenes which carried a strongly electron-withdrawing group (CN, CO₂Me) did not react. The reaction with β-alkylstyrenes 6 was successful for the methyl substituted substrate 6a and yielded (88%) trans-5-methyl-4-phenyl-1,3-dioxane (7a) preferentially (dr = 75:25). For steric reasons, other β-alkylstyrenes 6b-d did not react. The remarkable stereodiscrimination attained by catalyst 1 was employed in the regioselective transformation of 4-propenylstyrene (10) to dioxane 11 (83% yield).

carbocations - catalysis - chemoselectivity - electrophilic additions - Lewis acids

References

1a Prins HJ. Chem. Weekbl.  1919,  16:  1072 ; Chem. Abstr. 1919, 13, 3155

1b Prins HJ. Proc. Acad. Sci. (Amsterdam)  1919,  22:  51 ; Chem. Abstr. 1920, 14, 1662

Reviews:

2a Arundale E. Mikeska LA. Chem. Rev.  1952,  51:  505 

2b Adams DR. Bthnagar SP. Synthesis  1977,  661 

3 Okachi T. Fujimoto K. Onaka M. Org. Lett.  2002,  4:  1667 ; and references cited therein

Reviews:

4a Snider BB. In Comprehensive Organic Synthesis   Vol. 2:  Trost BM. Fleming I. Pergamon; London: 1991.  p.527 

4b Nubbemeyer U. In Methoden der Organischen Chemie (Houben-Weyl)   Vol. E21c, 4th ed.:  Helmchen G. Hoffmann RW. Mulzer J. Schaumann E. Thieme; Stuttgart: 1995.  p.2295 

4c Overman LE. Pennington LD. Can. J. Chem.  2000,  78:  732 

For recent reports on stereoselective variants of the Prins reaction, see the following references, and the references cited therein:

5a Kocovsky P. Ahmed G. Srogl J. Malkov AV. Steele J. J. Org. Chem.  1999,  64:  2765 

5b Pansare SV. Jain RP. Org. Lett.  2000,  2:  175 

5c Ishihara K. Nakamura H. Yamamoto H. Synlett  2000,  1245 

5d Zhang W.-C. Li C.-J. Tetrahedron  2000,  56:  2403 

5e Cohen F. MacMillan DWC. Overman LE. Romero A. Org. Lett.  2001,  3:  1225 

5f Lebsack AD. Overman LE. Valentekovich RJ. J. Am. Chem. Soc.  2001,  123:  4851 

5g Jaber JJ. Mitsui K. Rychnovsky SD. J. Org. Chem.  2001,  66:  4679 

5h Kimura M. Ezoe A. Tanaka S. Tamaru Y. Angew. Chem. Int. Ed.  2001,  40:  3600 

5i Braddock DC. Badine DM. Gottschalk T. Synlett  2001,  1909 

6 Comprehensive treatment: Lewis Acids in Organic Synthesis   Yamamoto H. Wiley-VCH; Weinheim: 2000. 

For previous work related to catalytic Prins reactions of styrenes, see:

7a Delmas M. Gaset A. Synthesis  1980,  871 

7b Thioville-Cazat J. Tkatchenko I. J. Chem. Soc., Chem. Commun.  1982,  1128 

7c Chandrasekhar S. Subba Reddy BV. Synlett  1998,  851 

7d Aramendía MA. Borau V. Jiménez C. Marina JM. Romero FJ. Urbano FJ. Catal. Lett.  2001,  73:  203 

For reviews on the use of bulky designer Lewis acid catalysts, see:

8a Saito S. Yamamoto H. Pure Appl. Chem.  1999,  71:  239 

8b Saito S. Yamamoto H. Chem. Commun.  1997,  1585 

9 v. Steuber E. Elter G. Noltemeyer M. Schmidt H.-G. Meller A. Organometallics  2000,  19:  5083 

10 All substituent constants were taken from: Exner O. Correlation Analysis of Chemical Data   Plenum Press; New York: 1988. 

11a

The trans-compound is commercially available.

11b A cis/trans-mixture can be obtained according to: Martles BA. Saint CG. Traynor JR. J. Chem. Soc., Perkin Trans. 1  1986,  567 

12 Dolby LJ. Wilkins C. Frey TG. J. Org. Chem.  1966,  31:  1110 

13 Styrene 10 was obtained by Wittig reaction starting from terephthalaldehyde, according to: Le Bigot Y. Delmas M. Gaset A. Synth. Commun.  1983,  13:  177 

14a Zhuo J.-C. Wyler H. Helv. Chim. Acta.  1999,  82:  1122 

14b

The same protocol was used to obtain compound 4h from 3-vinylaniline.

15 A cross-coupling protocol was used to obtain compound 4j from 3-bromothiophene and 4k from 2-bromothiophene: Tamao K. Sumitani K. Kiso Y. Zembayashi M. Fujioka A. Komada S.-i. Nakajima I. Minato A. Kumada M. Bull. Chem. Soc. Jpn.  1976,  49:  1958 

16 Still WC. Kahn M. Mitra AJ. J. Org. Chem.  1978,  43:  2923 

17 Tateiwa J. Hashimoto K. Yamauchi T. Uemura S. Bull. Chem. Soc. Jpn.  1996,  69:  2361 

18 Ferrand G. Huet J. Bull Soc. Chim. Fr.  1973,  3122