Syntheses of enantiomerically pure tetrahydrofuran building blocks for nactin and pamamycin antibiotics via an enzymically resolved .gamma.-hydroxyallene

1993 ◽  
Vol 58 (23) ◽  
pp. 6486-6490 ◽  
Author(s):  
Robert D. Walkup ◽  
Sang Woong Kim ◽  
Stephen D. Wagy
Keyword(s):  
Building Blocks ◽  
Enantiomerically Pure

Biocatalysis as a useful tool in pheromone synthesis. Enantiomerically pure building blocks from baker's yeast reductions and enzyme catalysed resoluti

1994 ◽  
Vol 22 (3) ◽  
pp. 591-606 ◽  
Author(s):  
H.-E. Högberg ◽  
P. Berglund ◽  
H. Edlund ◽  
J. Fägerhag ◽  
E. Hedenström ◽  
...  
Keyword(s):  
Building Blocks ◽  
Baker’S Yeast ◽  
Baker's Yeast ◽  
Enantiomerically Pure

Enantioselective synthesis of structurally intricate and complementary polyoxygenated building blocks of Spongistatin 1 (Altohyrtin A)

2009 ◽  
Vol 74 (5) ◽  
pp. 651-769 ◽  
Author(s):  
Alain Braun ◽  
Il Hwan Cho ◽  
Stephane Ciblat ◽  
Dean Clyne ◽  
Pat Forgione ◽  
...  
Keyword(s):  
Suzuki Coupling ◽  
Building Blocks ◽  
Enantioselective Synthesis ◽  
Side Chain ◽  
Spongistatin 1 ◽  
Enantiomerically Pure ◽  
Altohyrtin A ◽  
Stereogenic Centers ◽  
Complex Building ◽  
Synthetic Effort

Enantioselective approaches to the construction of four complex building blocks of the structurally intricate marine macrolide known as spongistatin 1 are presented. The first phase of the synthetic effort relies on a practical approach to a desymmetrized, enantiomerically pure spiroketal ring system incorporating rings A and B. Concurrently, the C17–C28 subunit, which houses one-fifth of the stereogenic centers of the target in the form of rings C and D, was assembled via a composite of stereocontrolled aldol condensations. Once arrival at the entire C1–C28 sector had been realized, routes were devised to provide two additional highly functionalized sectors consisting of C29–C44 and C38–C51. A series of subsequent transformations including cyclization of the E ring and hydroboration to afford the B-alkyl intermediate for the key Suzuki coupling to append the side chain took advantage of efficient stereocontrol. Ultimately, complete assembly and functionalization of the western EF sector of spongistatin was thwarted by an inoperative Suzuki coupling step intended to join the side chain to the C29–C44 sector, and later because of complications due to protecting groups, which precluded the complete elaboration of the late stage C29–C51 intermediate.

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