washed with brine dried over mgso 4 and concentrated under reduced pressure to give 144 mg 99 yield of the crude product 7a as colorless oil the crude product was sufficiently pure for the subsequent reaction 1 h nmr 300 mhz cdcl 3 u03b40 28 s 9h 0 78 t j 7 4 hz 3h 1 9 m 2h 2 13 m 2h 3 43 s 3h 3 59 m 1h 3 7 m 1h 4 0 s 3h 4 71 s 2h 4 89 d j 10 6 hz 1h 5 09 d j 10 6 hz 1h 6 91 s 1h 13 c nmr 75 mhz cdcl 3 u03b4 u2212 1 94 7 64 36 44 43 73 48 78 53 61 55 73 60 06 69 97 80 87 96 23 116 71 121 23 153 73 162 64 164 08 ir film nacl cm u2212 1 3383 2962 1545 1342 1038 839 lrms 70 ev ei m z rel int 339 m u2212 h 2 o 324 308 294 266 250 85 73 100 57 hrms m z calcd for c 17 h 29 no 4 si m u2212 h 2 o 339 1866 found 339 1876 u03b1 23 d u2212 1 9 c 1 05 ch 2 cl 2 to a mixture of 7a 0 75 g 2 1 mmol.