Intramolecular Ketalization of Functionalized 7-Norbornenols

Abstract

Convenient access to polycondensed heterocyclic networks has been realized through exposure of bridged hydroxy acetonides to appropriate reagents.

Key words - photochemistry - heterocycles - acetals - sulfones - sulfoxides

References

• For reports on efforts towards the synthesis of pseudolaric acid A(1), see:
• 1a Geng Z. Chen B. Chiu P. Angew. Chem. Int. Ed.  2006,  45:  6197 
• 1b Chen B. Ko RYY. Yuen MSM. Cheng KF. Chiou P. J. Org. Chem.  2003,  68:  495 
• 1c Chiu P. Chen B. Cheng KF. Org. Lett.  2001,  3:  1721 
• 1d Ou L. Hu Y. Song G. Bai D. Tetrahedron  1999,  55:  13999 
• 1e Hu Y. Ou L. Bai D. Tetrahedron Lett.  1999,  40:  545 
• 1f Chiu P. Chen B. Cheng KF. Tetrahedron Lett.  1998,  39:  9229 
• 1g Pan BC. Chang HY. Cai GL. Guo YS. Pure Appl. Chem.  1989,  61:  389 
• 2a Zhou BN. Ying BP. Song GQ. Chen ZX. Han J. Yan YF. Planta Med.  1983,  47:  35 
• 2b Yao JX. Lin XY. Acta Chim. Sin. (Engl. Ed.)  1982,  40:  385 
• 3a Cargill RL. Peet NP. Pond DM. Bundy WA. Sears AB. J. Org. Chem.  1980,  45:  3999 
• 3b Cargill RL. Sears AB. Boehm J. Willcott MR. J. Am. Chem. Soc.  1973,  95:  4346 
• 3c Cargill RL. King TY. Sears AB. J. Org. Chem.  1971,  36:  1423 
• 3d Cargill RL. Sears AB. Willcott MR. J. Am. Chem. Soc.  1970,  92:  6084 
• 3e Cargill RL. Gimare BM. Pond DM. King TY. Sears AB. Willcott MR. J. Am. Chem. Soc.  1970,  92:  3809 
• 4 Basil LF. Nakano H. Frutos R. Kopach M. Meyers AI. Synthesis  2002,  2064 
• 5 Snider BB. Allentoff AJ. Kulkarni YS. J. Org. Chem.  1988,  53:  5320 
• 6a Langer K. Mattay J. J. Org. Chem.  1995,  60:  7256 
• 6b Salomon RG. Coughlin DJ. Ghosh S. Zagorski MG. J. Am. Chem. Soc.  1982,  104:  998 
• 7 More JD. Finney NS. Org. Lett.  2002,  4:  3001 
• 8 Nicolaou KC. Montagnon T. Baran PS. Angew. Chem. Int. Ed.  2002,  41:  1386 
• 9 The use of catalytic Pd(OAc)₂ resulted in lower yields. See: Larock RC. Hightower TR. Kraus GA. Hahn P. Zheng D. Tetrahedron Lett.  1995,  36:  2423 
• 10 Rigby JH. Wilson JAZ. J. Org. Chem.  1987,  52:  34 
• 11 This material was found to contain a small amount of the corresponding syn-alcohol (10:1 anti/syn). The assignment of the relative stereochemistry at the newly formed stereogenic center was made on the basis of the ^¹H NMR chemical shifts of the signals corresponding to the vinyl and bridgehead protons (anti δ = 5.29/syn δ = 5.55 and anti δ = 2.29/syn δ = 2.38, respectively). See: Clark FRS. Warkentin J. Can. J. Chem.  1971,  49:  2223 
• For examples of the McMurry reaction used to for polycycles containing seven-membered rings, see
• 12a Dauben WG. Farkas I. Bridon DP. Chuang CP. Henegar KE. J. Am. Chem. Soc.  1991,  113:  5883 
• 12b Lee E. Yoon CH. Tetrahedron Lett.  1996,  37:  5929 
• 13a Roberts JD. Johnson FO. Carboni RA. J. Am. Chem. Soc.  1954,  76:  5692 
• 13b Winstein S. Shatavsky M. Norton C. Woodward RB. J. Am. Chem. Soc.  1955,  77:  4183 
• 14 For examples of α-sulfonyl sulfones being used in Ramberg-Bäcklund ring contraction reactions, see: Scarpetti D. Fuchs PL. J. Am. Chem. Soc.  1990,  112:  8084 
• 15 Armarego WLF. Perrin DD. Purification of Laboratory Chemicals   4th ed.:  Butterworth-Heinemann; Oxford: 1997. 
• 16 Still WC. Kahn M. Mitra A. J. Org. Chem.  1978,  43:  2923 

17

Signal disappeared upon the addition of a drop of D₂O to the NMR sample.