Magnus s synthesis

Magnus prepared tetrahydrobenzofuran 37 using a Feist-Benary reaction of ethyl 2-chloroacetoacetate (32) and functionalized 1,3-cyclohexanedione 36. Compound 37 was a key synthetic intermediate in Magnus s synthesis of linderalactone, isolinderalactone, and niolinderalactone. ... 

Scheme 21. The Barton reaction in Magnus s synthesis of grandisol (117).

Cyclobutane.—Further reports of grandisol (90) synthesis include Magnus s full paper (Vol. 6, p. 22) and an almost identical Japanese report of an earlier synthesis (Vol. 3, p. 25) based upon a dihydropyranone-ethylene cycloaddition.A third synthesis utilizes cyclopropanation of 4-methoxy-3,6,6-trimethylcyclohexa-2,4-dienone to yield (91) followed by rearrangement of the a-oxycyclopropylcarbinyl cation of (91) to (92). After reduction of the cyclobutanone, second-order Beckmann cleavage of the cyclopentanone oxime gave (93) from which grandisol (90) was readily obtained. 

Morphine s synthesis remains a serious challenge to this day. Until recently, the formal synthesis published by Kenner Rice [16] was its most efficient preparation. In 2009, Magnus reported a route to codeine with a reported overall yield of approximately 17% [17]. All academic s)mtheses reported in the literature, creative as these may be, suffer from lack of practicality, with the sole exception of Rice s disclosure, which has potential for scale-up. 

Nearly 40 years after Woodward s pioneering work (19,20), Magnus et al. accomplished the second total synthesis of strychnine using a transannular oxidative cyclization (56,57), which simultaneously constructed the C and D rings, as the key reaction (Scheme 3). Magnus strychnine synthesis began with... 

N. S. Simpkins, Sulphones in Organic Synthesis [Tetrahedron Organic Chemistry], (J. E. Baldwin and R D. Magnus, eds.), Pergamon Press, Oxford, 1993. 

R.M. Williams, Synthesis of Optically Active a-Amino-Acids- in J. E. Baldwin u. P. D. Magnus, Organic Chemistry Series Vol. 7, S. 270, Pergamon Press, Oxford New York Beijing Frankfurt Sao Paulo Tokyo - Toronto 1989. 

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