Funny you should ask: No.
That is a real issue with Krisflyer. They want the miles in your account before they will ticket or even hold the reservation. Since AMEX MR to Krisflyer isn't instantaneous (why is that? isn't it computer to computer?), you run a risk of not having the reservation available when the miles "hit" your Krisflyer account. However, I think once you initiate the transfer, after a day or so you can get a "confirm number," or some such thing, from AMEX MR, showing that the miles are en route to Krisflyer. With that, they may be able to ticket/hold the reservation.
Good luck.
One more thing, though AMEX says once the miles are transferred, they are gone for good, if you do transfer them, and the SQ ticket is no longer available, you can then turn back to AMEX and depending on how well you plead, get AMEX to recoup the miles back to your MR account.