Chiral Carbanions, Part 4: [1] Borylation of (Trimethylsilyl)methyl N,N-Dialkylcarbamates - Diastereoselectivity and Structural Studies

Abstract

(Trimethylsilyl)methyl carbamates were prepared from (trimethylsilyl)methanol and N,N-dialkylcarbamoyl chlorides and were metalated by s-BuLi/TMEDA. The configurationally labile lithiated carbamates were reacted with borates derived from (+)-pinane-2,3-diol to give boronates diastereoselectively (yields up to 84%, dr up to 17:1). The absolute configurations at the boron-bearing carbon atoms of three boronates were assigned by single crystal X-ray structure analyses.

carbamates - carbanions - lithiation - nucleophilic substitution - diastereoselectivity

References

<A NAME="RT05404SS-1">1</A> Part 3: Hammerschmidt F. Hanninger A. Peric Simov B. Völlenkle H. Werner A. Eur. J. Org. Chem.  1999,  3511 

<A NAME="RT05404SS-2A">2a</A> Köster R. In Houben-Weyl Methods of Organic Chemistry   4th ed., Vol. 13, 3a:  Köster R. Thieme; Stuttgart: 1982.  p.616 

<A NAME="RT05404SS-2B">2b</A> Matteson DS. Tetrahedron  1989,  45:  1859 

<A NAME="RT05404SS-3A">3a</A> Miyaura N. Suzuki A. Chem. Rev.  1995,  95:  2457 

<A NAME="RT05404SS-3B">3b</A> Kotha S. Lahiri K. Kashinath D. Tetrahedron  2002,  58:  9633 

<A NAME="RT05404SS-4A">4a</A> Roush WR. In Houben-Weyl Methods of Organic Chemistry   4th ed., Vol. E 21b:  Helmchen G. Hoffmann RW. Mulzer J. Schaumann E. Thieme; Stuttgart: 1995.  p.1410 

<A NAME="RT05404SS-4B">4b</A> Hoffmann RW. Angew. Chem., Int. Ed. Engl.  1982,  21:  555 

<A NAME="RT05404SS-5">5</A> Matteson DS. Tetrahedron  1998,  54:  10555 

<A NAME="RT05404SS-6">6</A> Cain ChM. Cousins RPC. Coumbarides G. Simpkins NS. Tetrahedron  1990,  46:  523 

<A NAME="RT05404SS-7">7</A> Ambasht S. Chiu SK. Peterson PE. Queen J. Synthesis  1980,  318 

<A NAME="RT05404SS-8">8</A> Carstens A. Hoppe D. Tetrahedron  1994,  50:  6097 

<A NAME="RT05404SS-9">9</A> Andersen MW. Hildebrandt B. Köster G. Hoffmann RW. Chem. Ber.  1989,  122:  1777 

<A NAME="RT05404SS-10">10</A> Matteson DS. Man H.-W. J. Org. Chem.  1996,  61:  6047 

<A NAME="RT05404SS-11">11</A> As the nomenclature of boronates is complex, the practical system of Matteson et al. is adopted: Matteson DS. Kandil AA. Soundararajan R. J. Am. Chem. Soc.  1990,  112:  3964 

<A NAME="RT05404SS-12">12</A> Basu A. Thayumanavan S. Angew. Chem. Int. Ed.  2002,  41:  716 

<A NAME="RT05404SS-13">13</A> Hoppe D. Hense T. Angew. Chem., Int. Ed. Engl.  1997,  36:  2282 

<A NAME="RT05404SS-14">14</A> Hoppe D. Paetow M. Hintze F. Angew. Chem., Int. Ed. Engl.  1993,  32:  394 

<A NAME="RT05404SS-15A">15a</A> Horeau A. Kagan H.-B. Vigneron J.-P. Bull. Soc. Chim. Fr.  1968,  3795 

<A NAME="RT05404SS-15B">15b</A> Masamune S. Choy W. Petersen JS. Sita LR. Angew. Chem., Int. Ed. Engl.  1985,  24:  1 

<A NAME="RT05404SS-16">16</A> Lee S.-G. Magn. Reson. Chem.  2002,  40:  311 

<A NAME="RT05404SS-17">17</A> Matteson DS. Sadhu KM. Peterson ML. J. Am. Chem. Soc.  1986,  108:  810 

<A NAME="RT05404SS-18">18</A> Wrackmeyer B. Köster R. In Houben-Weyl Methods of Organic Chemistry   4th ed., Vol. 13, 3c:  Köster R. Thieme; Stuttgart: 1984.  p.377 

<A NAME="RT05404SS-19">19</A> Mikenda W. Vib. Spectrosc.  1992,  3:  327 

<A NAME="RT05404SS-20">20</A>

DENZO-SMN program package, Nonius B. V., The Netherlands.

<A NAME="RT05404SS-21">21</A> Sheldrick GM. SHELXS-97, A program for the solution of crystal structures   Universität Göttingen; Germany: 1997. 

<A NAME="RT05404SS-22">22</A> Sheldrick GM. SHELXS-97, A program for crystal structure refinement   Universität Göttingen; Germany: 1997. 

<A NAME="RT05404SS-23">23</A>

The structural data of compounds 10, 12c and 13b have been deposited at the Cambridge Crystallographic Data Centre under the reference numbers CCDC 239224, 239226, 239225, respectively. Copies of the data can be obtained free of charge on application to CCDC, 12 Union Road, Cambridge CB2 1EZ, UK [Fax: [phone]; e-mail: [e-mail]].