Synthesis and structure of 6-exo-hydroxy-1,2-diphenyl-1-phosphoniatricyclo [3.3.1.1]decane iodide, a derivative of 1-phosphaadamantane

✍ Scribed by H. J. Meeuwissen; G. Sirks; F. Bickelhaupt; C. H. Stam; A. L. Spek

• Book ID: 104588471
• Publisher: Elsevier Science
• Year: 2010
• Tongue: English
• Weight: 809 KB
• Volume: 101
• Category: Article
• ISSN: 0165-0513
• DOI: 10.1002/recl.19821011205

✦ Synopsis

Abstract

The annelation reaction between l,2,3,6‐tetrahydro‐1‐phenyl‐4‐(1‐pyrrolidinyl)phosphorin 1‐oxide (10) and 2,2‐bis(chloromethyl)acetophenone (7) leads to two stereoisomeric 7‐benzoyl‐3‐phenyl‐3‐phosphabicyclo[3.3.1]nonan‐9‐one 3‐oxides 11a and 11b. Their difference resides in the configuration at phosphorus, which also determines the conformation of the bicyclononane skeleton, as revealed from the crystal structures. Reduction of the two keto functions in 11a with NaBH~4~ to give 12a, followed by HSiCl~3~ reduction to the phosphine 13a and acid‐catalyzed ring closure, yields the title compound (4a), the structure of which was corroborated by an X‐ray crystal structure determination. Interestingly, the same sequence of reactions converts 11b into a 3.3 : 1 mixture of 4a and 4b; presumably, inversion of configuration at phosphorus occurs in the last step and is catalyzed by acid.